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Balbharti Maharashtra State Board Class 11 Secretarial Practice Important Questions Chapter 7 Company Meetings – I Important Questions and Answers.

Maharashtra State Board 11th Secretarial Practice Important Questions Chapter 7 Company Meetings – I

1A. Select the correct answer from the options given below and rewrite the statements.

Question 1.
The business to be transacted at the meeting is called _____________
(a) Agenda
(b) Minutes
(c) Notice
Answer:
(a) Agenda

Question 2.
A proxy form must be deposited in the registered office of the company at least _____________ hours before the meeting.
(a) 48
(b) 24
(c) 12
Answer:
(a) 48

Question 3.
A copy of the special resolution must be filed with the registrar within _____________ days of the passing resolution.
(a) 30
(b) 60
(c) 90
Answer:
(a) 30

Question 4.
Quorum for a private company is _____________ members.
(a) 15
(b) 5
(c) 2
Answer:
(c) 2

Question 5.
Point of order can be raised by _____________
(a) Chairman
(b) Secretary
(c) Member
Answer:
(c) Member

Question 6.
One share one vote’ is a voting method following under _____________
(a) voting by show of hands
(b) voting by ballot
(c) voting by-poll
Answer:
(c) voting by-poll

Question 7.
A motion which is changed due to an amendment is called _____________ motion.
(a) Formal
(b) Substantive
(c) Closure
Answer:
(b) Substantive

1B. Match the pairs.

Question 1.

Group ‘A’	Group ‘B’
(a) Agenda	(1) Alteration in the original motion
(b) Amendment	(2) Extra vote for chairman
(c) Point of Order	(3) Rejected a motion
(d) Casting Vote	(4) Objection raised by a member in the meeting
(e) Resolution	(5) List of items to be transacted at the meeting
	(6) Alteration in a Resolution
	(7) Suggestion given by the member in the meeting
	(8) Accepted Motion
	(9) Only important items to be discussed at the meeting
	(10) Extra vote for Directors

Answer:

Group ‘A’	Group ‘B’
(a) Agenda	(5) List of items to be transacted at the meeting
(b) Amendment	(1) Alteration in the original motion
(c) Point of Order	(4) Objection raised by a member in the meeting
(d) Casting Vote	(2) Extra vote for chairman
(e) Resolution	(8) Accepted Motion

1C. Write a word or a term or a phrase that can substitute each of the following statements.

Question 1.
A list of items to be transacted at the meeting.
Answer:
Agenda

Question 2.
The minimum number of members to be present for a valid meeting.
Answer:
Quorum

Question 3.
The person who presides over the meeting.
Answer:
Chairman

Question 4.
A proposal is put before the meeting for discussion and decision.
Answer:
Motion

Question 5.
A motion finally passed at the meeting.
Answer:
Resolution

Question 6.
An alteration was proposed to the original motion.
Answer:
Amendment

Question 7.
A motion which brings to the notice of the Chairman the irregularities at the meeting.
Answer:
Point of Order

Question 8.
A person appointed by a member to attend and vote at the meeting.
Answer:
Proxy

Question 9.
An extra vote for the Chairman in case of tie-in votes.
Answer:
Casting vote

1D. State whether the following statements are True or False.

Question 1.
A proxy can vote under the poll method.
Answer:
True

Question 2.
Notice of the meeting must be given 14 days in advance.
Answer:
False

Question 3.
An agenda is sent along with the notice.
Answer:
True

Question 4.
Secretary has to sign the minutes book.
Answer:
False

Question 5.
Motion is a final decision of the meeting.
Answer:
False

Question 6.
Alteration can be done only by adding some new words.
Answer:
False

Question 7.
Point of Order is an objection raised by a member.
Answer:
True

Question 8.
Chairman can exercise casting votes in case of tie-in votes.
Answer:
True

Question 9.
A proxy cannot speak at the meeting.
Answer:
True

Question 10.
Secrecy can be maintained under voting by the show of hands method.
Answer:
False

Question 11.
A proxy need not be a member of the company.
Answer:
True

1E. Find the odd one.

Question 1.
Ordinary, Resolution, Special Resolution, Formal Motion.
Answer:
Formal Motion

Question 2.
Voting by voice, Voting by Ballot, Casting vote.
Answer:
Casting vote

Question 3.
Formal Motion, Substantive Motion, Resolution.
Answer:
Resolution

Question 4.
Voting by Poll, Voting by show of hands, Virtual voting.
Answer:
Virtual voting

Question 5.
Bare Statement Agenda, Draft Minutes Agenda, Minutes.
Answer:
Minutes

1F. Complete the sentences.

Question 1.
A person who presides over the meeting is known as _____________
Answer:
Chairman

Question 2.
Agenda is sent along with _____________
Answer:
Notice

Question 3.
Quorum for a private company is _____________
Answer:
2 members

Question 4.
A person responsible for proper conduct and to maintain order in the meeting is _____________
Answer:
Chairman

Question 5.
A motion which is changed due to amendment is called _____________
Answer:
Substantive motion

Question 6.
A resolution passed by simple majority is called _____________
Answer:
Ordinary Resolution

Question 7.
A special resolution, within 30 days of its passing must be filed with _____________
Answer:
Registrar of Companies

Question 8.
A representative of a member in a meeting is called _____________
Answer:
Proxy

1G. Select the correct option from the bracket.

Question 1.

Group ‘A’	Group ‘B’
(1) Voting by voice	……………………..
(2) …………………	21 clear days
(3) Up to 1000 shareholders	……………………
(4) ……………………..	15 days
(5) More than 5000 shareholders	…………………….
(6) ……………………	Writing
(7) Voting by Poll	…………………….
(8) ……………………	Objection
(9) Resolution by circulation	……………………
(10) …………………	Chairman

(Casting vote, Point of order, Directors, Motion, Secret method, Quorum is 5 members, Notice, Yes or No, Quorum is 30 members, Minutes)
Answer:

Group ‘A’	Group ‘B’
(1) Voting by voice	Yes or No
(2) Notice	21 clear days
(3) Up to 1000 shareholders	Quorum is 5 members
(4) Minutes	15 days
(5) More than 5000 shareholders	Quorum is 30 members
(6) Motion	Writing
(7) Voting by-poll	Secret method
(8) Point of order	Objection
(9) Resolution by circulation	Directors
(10) Casting vote	Chairman

1H. Answer in one sentence.

Question 1.
What is a quorum?
Answer:
Quorum is the minimum number of members required to be present for a valid meeting.

Question 2.
What is a proxy?
Answer:
A proxy is a person, who can attend and vote at the meeting on behalf of an absent member.

Question 3.
What is motion?
Answer:
A motion is a proposal put before the meeting for discussion and decision.

Question 4.
What is Resolution?
Answer:
A motion accepted in a meeting is called Resolution.

1I. Correct the underlined word and rewrite the following sentences.

Question 1.
The minimum number of members required to be present at a meeting’s called proxy.
Answer:
The minimum number of members required to be present at a meeting’s called Quorum.

Question 2.
Director draft s the minutes of a meeting.
Answer:
Secretary draft s the minutes of a meeting.

Question 3.
Voting by show of hands is a capitalistic method.
Answer:
Voting by show of hands is a democratic method.

Question 4.
The ordinary resolution requires a 75% majority of votes.
Answer:
A special resolution requires a 75% majority of votes.

Question 5.
Agenda is a record of business transacted at the meeting.
Answer:
Minutes is a record of business transacted at the meeting.

Question 6.
A notice period of general meeting needs 7 clear days.
Answer:
A notice period of general meeting needs 21 clear days.

1J. Arrange in proper order.

Question 1.
(a) Chairman
(b) Agenda
(c) Amendment
Answer:
(a) Agenda
(b) Chairman
(c) Amendment

Question 2.
(a) Point of order
(b) Quorum
(c) Motion
Answer:
(a) Quorum
(b) Motion
(c) Point of order

2. Distinguish between the following.

Question 1.
Motion and Amendment
Answer:

Basis	Motion	Amendment
1. Meaning	Motion is a written proposal placed before the meeting for decision and discussion.	An amendment is an alteration or modification proposed to the original motion.
2. Purpose	The main purpose of the motion is to discuss and to make proper decisions.	The main purpose of an amendment is to revise or modify the main motion.
3. Right to speak	Every member can speak only once either in favour or against the motion.	Only those members who have not spoken on the original motion can speak on an amendment.
4. Effect	When a motion is accepted by the majority in the meeting, it becomes a resolution.	When an amendment is approved by the majority, it becomes a part of the resolution.
5. Mover	Mover of the motion can speak twice on his own motions.	Mover of the amendment can speak only once on his own amendment.

Question 2.
Ordinary Resolution and Special Resolution
Answer:

Basis	Ordinary Resolution	Special Resolution
1. Meaning	The resolution which is passed by a simple majority of votes is called Ordinary resolution.	The resolution which is passed by 3/4th majority of votes is called a Special resolution.
2. Majority	It requires more than 50% of the majority.	It requires at least a 75% majority of votes.
3. Filing	It is not filed with the Registrar of companies.	It is filed with the Registrar of companies within 30 days of passing the resolution.
4. Business transacted	It is necessary for routine and ordinary business.	It is necessary for special business.
5. Examples	Appointment of auditors, declaration of dividend, the election of directors, etc.	Change in the name of the company, alteration in object clause, reduction in spare capital, etc.

3. Answer in brief.

Question 1.
State the importance of the Agenda.
Answer:
Agenda is a list of items to be discussed or things to be done or the business to be transacted at the meeting. It is sent along with the notice. A secretary prepares the agenda in consultation with the Chairman.
Importance of Agenda:

• Members come to know about the matter to be discussed at the meeting.
• Members can come well prepared for the meeting, as the agenda is sent along with notice (21 clear days) before the meeting.
• The agenda helps the chairman to conduct the meeting efficiently.
• Items can be discussed as per the order mentioned in the agenda.
• All items are discussed at the meeting. Routine matters are discussed first, followed by special matters.

Question 2.
State the provisions regarding Quorum.
Answer:
Quorum is the minimum number of members required to be present for transacting a valid business. Without a quorum, the proceeding of the meeting becomes invalid. The quorum should be present throughout the meeting i.e. from beginning till the end of the meeting. Secretary must check the quorum before the commencement of the meeting.

Provision relating to Quorum (Companies Act, 2013)
(i) Quorum for General Meeting:

In the case of a Public Company: Quorum depends on a number of shareholders.

No. of shareholders	Quorum
Up to 1000	5 members
1000 – 5000	15 members
More than 5000	30 members

In the case of a Private Company: Two members personally present shall be the quorum for the meeting.

(ii) Quorum for Board Meeting:
According to the provision in the Companies Act, a quorum for the board meeting is l/3rd of its total directors or two directors whichever is higher. Any fraction should be rounded to one.

4. Justify the following statements.

Question 1.
Resolution cannot be amended
Answer:
(i) When a motion is accepted in a meeting it becomes a resolution.
(ii) When a motion is under discussion it can be amended.
(iii) Resolution is a final decision, it cannot be changed.
(iv) Motion is passed in the meeting after a required discussion on a particular matter.
(v) A resolution cannot be amended as it is a final decision taken in the meeting.
Thus, the resolution cannot be amended.

Question 2.
Quorum is required throughout the meeting.
Answer:

• a minimum number of members required for a valid meeting is a quorum.
• Members present in the beginning should be present during the entire period of the meeting.
• If the quorum is not present, the meeting stands adjourned for the next week same day, same time, and same place.
• In the absence of a quorum, if any meeting is conducted it is considered an invalid meeting.
• If any resolution is passed in the absence of a quorum, then such resolution is considered an invalid and illegal resolution.
• Thus, a quorum is required throughout the meeting.

Question 3.
The chairman has the right of casting vote.
Answer:

• A casting vote is a special type of vote given only by the Chairman of the meeting.
• It is an additional vote given to the Chairman in case of equality of votes in favour and against a motion.
• The chairman can use his vote only in the case of a tie.
• This means when the votes cast for and against the resolution are equal.
• It is a decisive vote as the final decision depends on the manner in which it is used by the Chairman.
• The purpose of the casting vote is to have some definite decision on the matter for discussion before the meeting.
• As per the provision in the Articles of Association, this vote can be exercised only by the chairman of the meeting.
• Hence, the chairman has the right of casting vote.
• Thus, the chairman has the right of casting vote.

Question 4.
Minutes of a meeting, once approved cannot be changed.
Answer:

• Minutes are the factual and official records of the proceedings of the meeting in the form of decisions and resolutions.
• Minutes are the legal evidence of the proceedings conducted in a meeting.
• They cannot be changed once they are finalized and confirmed by the Chairman.
• If any rectification is to be done and is necessary, it is carried out by passing a resolution in the next meeting and recording the same in the minute’s book.
• Thus, the minutes of a meeting, once approved cannot be changed.

Question 5.
The agenda is useful to the chairman of the meeting.
Answer:

• Agenda means a list of items to be done at the meeting.
• It is a programme of the meeting.
• It is prepared by the secretary in consultation with the chairman.
• It is a guideline to the chairman of the meeting.
• It enables the chairman to conduct the business of the meeting in an orderly manner.
• Routine matters which can be discussed and decided in fewer times are arranged first in the serial order, after that special business or time-consuming matters.
• This makes it easy for the chairman to go through it and discuss the matters.
• Thus, the agenda is useful to the chairman of the meeting.

5. Answer the following questions.

Question 1.
Explain the kind of motion.
Answer:
A motion is a proposal put before the meeting for discussion and decision. A person who proposes a motion is called a proposer or a mover of a motion.
Kinds of Motion:

• Formal Motion
• Substantive Motion

(i) Formal Motion:
Formal motions are moved for the purpose of preventing or delaying or speeding up discussion on a motion.
Types of Formal Motion:
(a) Closure Motion:
This motion is moved when sufficient time is spent on the discussion of a particular motion. Any member can propose that ‘The question be now put’ to vote. This is a closure motion. The main object of this motion is to avoid waste of time and to arrive at a quick decision. If this motion is put to vote and if the majority approves, no further discussion is permitted.

(b) Previous Question Motion:
The main purpose of this motion is to prevent discussion on the main motion. When a member feels that it is unwise to consider the main motion, they may move the previous question. The wording of this motion is ‘The question be not now put’. If it is carried, the discussion on the main motion is dropped. If the previous question is lost, the original motion is put to vote.

(c) Next Business Motion:
The purpose of the motion is similar to the previous question motion. The wording of the motion is ‘The meeting to proceed to next business. Such a motion is moved when a member feels that the main motion under discussion is of little importance and other items of importance remain to be transacted. If it is carried, the original motion is dropped at once and the meeting proceeds to the next business.

(d) Adjournment of Debate Motion:
The main aim of this motion is to postpone the debate. The wordings of this motion are ‘The debate on the subject is adjourned’. The mover of the motion feels that some extra information is needed for further discussion and the discussion should be delayed for some time. If this motion is carried, the debate will be adjourned. If it is lost, the debate continues.

(e) Adjournment of Meeting:
The main aim of this motion is to postpone the meeting for a particular period or indefinite period. The wording of this motion is ‘The meeting be now adjourned’. If it is carried the meeting is postponed to a future date. If it is lost, the meeting continues.

(ii) Substantive Motion:
A motion that is changed due to an amendment is called a substantive motion. When an amendment is passed, it is incorporated in the original motion and the substantive motion is put to vote. If it is passed, it becomes a resolution.

Question 2.
Explain the essentials of notice of a meeting.
Answer:
Notice is an advance intimation given by the company informing the day, date, time, and place of meeting and business to be transacted at the meeting. It is given in writing to all those who are entitled to receive it.
(i) Essentials of the notice of a meeting:

• Nature and type of meeting.
• The exact day, date, time, and place of the meeting.
• The agenda of the meeting.
• A statement of a member entitled to attend the meeting and appoint a proxy.
• Any intention to pass a special resolution must be mentioned in the notice.
• Statutory note and explanation, if any special business is to be transacted.

(ii) Proper authority to send notice:
The Board of Directors is the proper authority to send the notice. Under exceptional circumstances, members of the National Company Law Tribunal or Central Government may send a notice for the meeting.

(iii) Proper authority to receive notice:

• All shareholders in case of the shareholders meeting.
• Auditors, in case of Annual General Meeting.
• The legal representative of the deceased or insolvent person.
• First name in Register of members, in case of joint holders.
• All directors in case of Board Meeting and General Meeting.

(iv) Period of Notice:
In the case of a general meeting, notice must be sent 21 clear days before the actual meeting (day of sending and day of meeting are excluded). In the case of a Board meeting, 7 days’ notice is required.

(v) Modes of serving notice:

• It can be sent either personally or by ordinary post at the registered address of the member in India.
• If no registered address in India, then it can be sent to the address, given by the members.
• It can be sent by registered post if requested by the member. Charges for the same are to be paid in advance.
• It is to be advertised in all leading newspapers, (English and regional language) where the registered office is situated.
• It can also be sent through electronic mode i.e. email.

(vi) A statement to be sent along with notice:
In case any special business is to be transacted in the general meeting, an explanatory statement to that effect is to be annexed to the notice.

(vii) Omission to give notice:
If notice is not served to one or more members deliberately, the meeting stands invalid.

Balbharti Maharashtra State Board Class 11 Secretarial Practice Important Questions Chapter 6 Directors and Key Managerial Personnel of a Company Important Questions and Answers.

Maharashtra State Board 11th Secretarial Practice Important Questions Chapter 6 Directors and Key Managerial Personnel of a Company

1A. Select the correct answer from the options given below and rewrite the statements.

Question 1.
DIN means __________
(a) Director Identification Number
(b) Secretary Identification Number
(c) Doctor Identification Number
Answer:
(a) Director Identification Number

Question 2.
Private company requires __________ Directors.
(a) 3
(b) 2
(c) 1
Answer:
(b) 2

Question 3.
COO means __________
(a) Chief Operating Officer
(b) Chief Financial Officer
(c) Chief Organization Officer
Answer:
(a) Chief Operating Officer

Question 4.
CS means __________
(a) Company Secretary
(b) Company Standard
(c) Chief Store Manager
Answer:
(a) Company Secretary

1B. Match the pairs.

Question 1.

Group ‘A’	Group ‘B’
(a) DIN	(1) Whole-time Director
(b) Executive Director	(2) Chief Executive Officer
(c) Key Managerial Personnel	(3) Alternate Director
(d) Company Secretary	(4) Director Identification Number
(e) Chief Financial Officer	(5) Member of ICWA
	(6) Officer responsible for Company’s finance
	(7) Member of ICSI
	(8) Officer responsible for Company’s Management

Answer:

Group ‘A’	Group ‘B’
(a) DIN	(4) Director Identification Number
(b) Executive Director	(1) Whole-time Director
(c) Key Managerial Personnel	(2) Chief Executive Officer
(d) Company Secretary	(7) Member of ICSI
(e) Chief Financial Officer	(6) Officer responsible for Company’s finance

1C. Write a word or a term or a phrase that can substitute each of the following statements.

Question 1.
DIN means.
Answer:
Director Identification Number

Question 2.
This is an audit that checks the compliance of the company.
Answer:
Secretarial Audit

Question 3.
It aims to achieve and integrate corporate practices to all companies.
Answer:
Secretarial Standard

Question 4.
As a principal officer of the company.
Answer:
Secretary

Question 5.
A Director who is in Whole Time Employment of the company.
Answer:
Whole Time Director

Question 6.
A first secretary appointed by the promoter.
Answer:
Pro-tem Secretary

Question 7.
Written proceeding of the meeting.
Answer:
Minutes

Question 8.
A person holding shares of nominal value ₹ 20,000.
Answer:
Small shareholders

Question 9.
Shares are required to be bought by the directors.
Answer:
Qualification shares

Question 10.
The person nominated on the Board by a dominant shareholder.
Answer:
Nominee Director

Question 11.
The director is in full-time employment with the company.
Answer:
Executive Director or Whole Time Director

Question 12.
Director designated as ‘Outside Director’.
Answer:
Nonexecutive Director

Question 13.
Fees paid to Directors for attending a Board meeting
Answer:
Sitting fees

1D. State whether the following statements are True or False.

Question 1.
A Directors include whole-time employment of company is called WTD.
Answer:
True

Question 2.
DIN is required for Directorship.
Answer:
True

Question 3.
Secretarial audit checks the compliance of the company.
Answer:
True

Question 4.
Secretary is not the principal officer of the company.
Answer:
False

Question 5.
Not providing guidance to the Board of Directors of the company is a general duty of the secretary.
Answer:
False

1E. Find the odd one.

Question 1.
Directors as Agents, as managing partners, As a company secretary.
Answer:
As a company secretary

Question 2.
First Directors, Casual vacancy, Audit.
Answer:
Audit

Question 3.
Chief Executive Officer, Chief Financial Officer, Promoter.
Answer:
Promoter

1F. Complete the sentences.

Question 1.
Statutory duties of secretary is to make all meetings __________
Answer:
minutes

Question 2.
There is no prohibition on having more than one in a company __________
Answer:
Managing Director

Question 3.
CFO is __________
Answer:
Chief Financial Officer

Question 4.
WTD means __________
Answer:
Whole Time Director

Question 5.
KMP is __________
Answer:
Key Managerial Personnel

1G. Select the correct option from the bracket.

Question 1.

Group ‘A’	Group ‘B’
(1) Managing Director	…………………………..
(2) …………………….	ICSI passed
(3) Manager	…………………………..
(4) Secretarial Audit	Checks the Legislations

(Substantial powers, Fulltime employee, Secretary, Checks the legislations)
Answer:

Group ‘A’	Group ‘B’
(1) Managing Director	Substantial powers
(2) Secretary	ICSI passed
(3) Manager	Full-time employee
(4) Secretarial Audit	Checks the Legislations

Question 2.

Group ‘A’	Group ‘B’
(1) First Director	……………………….
(2) …………………….	Key Managerial Personnel
(3) Pro-tem Secretary	……………………….
(4) Secretarial Standards	……………………….

(First Secretary, Appointed by the Promoter, Formulated by ICSI, Whole Time Director)
Answer:

Group ‘A’	Group ‘B’
(1) First Director	Appointed by the Promoter
(2) Whole Time Director	Key Managerial Personnel
(3) Pro-tem Secretary	First Secretary
(4) Secretarial Standards	Formulated by ICSI

1H. Answer in one sentence.

Question 1.
What do you mean by Nominee Director?
Answer:
The person nominated on the board by a major/dominant shareholder is known as the nominee director.

Question 2.
What do you mean by Independent Director?
Answer:
Independent Director is a director other than managing director, whole-time director, or a nominee director.

Question 3.
Which Companies have to appoint a Woman Director?
Answer:
Every listed company and the public company has a paid-up share capital of Rs. 100 crores or more and whose turnover is Rs. 300 crores or more, have to appoint a Woman Director.

Question 4.
What do you mean by Alternate Director?
Answer:
It means a director who is nominated by the board to act in the place of a director in his absence.

Question 5.
Who is in full-time employment with the company?
Answer:
The executive director (WTD) is in full-time employment with the company.

Question 6.
What do you mean by Qualification shares?
Answer:
Qualification shares are those shares that are to be bought by the intending director, so as to become a director of a company.

1I. Correct the underlined word and rewrite the following sentences.

Question 1.
RIN is the unique identification number of the director.
Answer:
DIN is the unique identification number of the director.

Question 2.
Whole-time Director is not involved in the day-to-day management of the company.
Answer:
Non-Executive Director is not involved in the day-to-day management of the company.

Question 3.
A company having paid-up share capital of ₹ 10 crores or more has to appoint a Woman Director.
Answer:
A company having paid-up share capital of ₹ 100 crores or more has to appoint a Woman Director.

Question 4.
Big Shareholder’s Directors is not a mandatory appointment.
Answer:
Small Shareholder’s Directors is not a mandatory appointment.

Question 5.
Directors are regarded as an employee of the company.
Answer:
Directors are regarded as an elected representatives of shareholders of the company.

Question 6.
A small shareholder is a person holding shares of a maximum of ₹ 50,000.
Answer:
A small shareholder is a person holding shares of a maximum of ₹ 20,000.

Question 7.
The manager needs to be the director of the company.
Answer:
The managing director needs to be the director of the company.

2. Explain the following Terms/Concepts.

Question 1.
Pro-tem Secretary
Answer:
The first secretary appointed by the promoters of the company is termed as Pro-tem Secretary. He may or may not be appointed as a regular secretary by the Board.

Question 2.
Sitting Fees
Answer:
Fees paid to the director for attending Board or Committee meeting is called as Sitting fees. It may extend up to Rs. one lakh also.

3. Answer in brief.

Question 1.
State the importance of DIN.
Answer:
Importance of DIN:

• It helps the investors to take accurate and appropriate decisions, as through DIN they get to know the composition of top management of the company.
• It helps to handle the problems arising due to the company creating fraud after raising capital from the investors.
• It helps to detect and handle offenses committed by a particular Director.

Question 2.
What are the general duties of a Company Secretary?
Answer:
General duties depend on the size and nature of the business.
Some of the general duties are as follows:

• To provide guidance to the Board and Director with respect to their duties, responsibilities, and powers.
• To represent before different regulators and authorities and discharge different duties under the Act.
• To assist the Board in the conduct of the affairs of the company.
• To assist and advise the Board in ensuring good corporate governance.
• To perform all the duties that may be assigned by the Board from time to time.

Question 3.
State the rights of a Company Secretary.
Answer:
Rights of a Company Secretary: Rights are given to the Secretary by the Companies Act, Board of Directors, and the Shareholders.
The rights of the Company Secretary are given below:

• Right to control and supervise the working of his department.
• Right to be indemnified by the company if any loss is suffered by Secretary while performing or discharging his duties.
• Right to sign a document requiring authentication.
• Right to get remuneration as an employee of the company.

Question 4.
State the importance of Secretarial Audit?
Answer:
Importance of Secretarial Audit:

• It provides a mechanism that monitors the compliance requirements.
• It detects errors and mistakes in compliance with companies’ rules and regulations mechanism.
• It prevents the company from the risk and losses due to non-compliance.
• It builds the confidence of regulators, management, and stakeholders.
• Investors feel relaxed that the company is following a disciplined approach towards management.

Balbharti Maharashtra State Board 12th Chemistry Important Questions Chapter 11 Alcohols, Phenols and Ethers Important Questions and Answers.

Maharashtra State Board 12th Chemistry Important Questions Chapter 11 Alcohols, Phenols and Ethers

Question 1.
What are alcohols? How are they classified?
Answer:
Alcohols are the hydroxy derivatives of hydrocarbons in which one or more hydrogen atoms are replaced by hydroxyl group.

Examples : CH₃ – OH methyl alcohol, CH₃ – CH₂ – OH ethyl alcohol. Depending on the basis of hydroxyl groups present in a molecule, alcohols are classified into monohydric, dihydric, trihydric and polyhydric alcohols.

Question 2.
What are monohydric alcohols? How are they classified?
Answer:
Alcohols having only one hydroxyl group in their molecules are called monohydric alcohols. Monohydric alcohols are classified according to the type of hybridization of the carbon atom to which the hydroxyl group is attached.

(1) Alcohols containing C_sp³ – OH bond : In these alcohols -OH group is attached to a sp³ – hybridised carbon atom of alkyl group. These alcohols are represented as R-OH. They are further classified as primary, secondary and tertiary alcohols in which – OH group is attached to primary, secondary and tertiary carbon atoms respectively.

(a) Allylic alcohols : In these alcohols -OH group is attached to a sp³ -hybridised carbon atom next to the carbon-carbon double bond i.e., to allylic carbon. Allylic alcohols may be primary, secondary and tertiary alcohols.

(b) Benzylic alcohols : In these alcohols -OH group is attached to a sp³ -hybridised carbon atom next to an aromatic ring. Benzylic alcohols may be primary, secondary and tertiary alcohols.

(2) Alcohols containing C_sp³ – OH bond: In these alcohols -OH group is attached to a sp² – hybridised carbon atom,
i.e., vinylic carbon. These alcohols are also called vinylic alcohols.
e.g., CH₂ = CH – OH vinyl alcohol.

Question 3.
What are phenols (carbolic acids)?
Answer:
Hydroxy derivatives of aromatic hydrocarbons in which the hydroxyl group is directly attached to the aromatic ring are called phenols.
Examples:

Question 4.
What is phenol? OR Define carbolic acid.
Answer:
The hydroxy derivative of benzene in which the OH group is directly attached to benzene ring is called phenol.

Question 5.
How are phenols classified? Give suitable examples.
Answer:
Phenols are classified on the basis of number of hydroxyl (- OH) groups present in a molecule of phenol.
(1) Monohydric phenols : Phenols contain one hydroxyl group in their molecule.

(2) Dihydric Phenols : Phenols contain two hydroxyl groups in their molecule.

(3) Trihydric phenols : Phenols contain three hydroxyl groups in their molecule.

Question 6.
What are ethers? How are ethers classified?
Answer:
They are alkoxy derivatives of alkanes in which a hydrogen atom of alkane (R – H) is replaced by alkoxy group ( – O – R) and divalent oxygen atom is attached to two alkyl groups or two aryl groups or one alkyl and one aryl group. Ethers are organic oxides R – O – Ar, Ar – O – Ar.
E.g. R – O – R or C₂H₅ – O – C₂H₅.

Ethers are classified into two groups as follows :
(1) Simple or symmetrical ether : The ethers in which both alkyl (or aryl) groups attached to the oxygen atom are same are called simple ethers.
E.g. (R – O – R), CH₃ – O – CH₃, dimethyl ether; C₆H₅ – O -C₆H₅ diphenyl ether.

(2) Mixed or unsymmetrical ethers : The ethers in which the two alkyl (or aryl) groups attached to the oxygen atom are different are called mixed ethers.
E.g. (R – O – R), CH₃ – O – C₂H₅ ethyl methyl ether; C₂H₅ – O – C₆H₅ ethyl phenyl ether.

Question 7.
What is the general formula of ethers?
Answer:
The general formula of ethers is C_nH_{2n + 2} O. For example, dimethyl ether CH₃ – O – CH₃ has molecular formula C₂H₆O.

Common nomenclature system :
(1) In this system, monohydric alcohols (R — OH) are named as alkyl alcohols.
(2) According to the attachment of hydroxyl group to a carbon atom they are named with prefixes as n-(normal or primary) alcohol, sec-(secondary) alcohol, tert-(tertiary) alcohol.
(3) Alcohols with two hydroxyl groups are named as glycols.

Carbinol system : In this system alcohols are considered as derivatives of methyl alcohol which is called carbinol. The alkyl group attached to the carbon carrying – OH group are named in alphabetical order. Then the suffix carbinol is added.

For example :

IUPAC system of nomenclature :

• In this system, alcohols are named as alkanols.
• A longest continuous chain of carbon atoms containing – OH group is chosen as a parent hydrocarbon and alcohol is considered as a hydroxy derivative of this alkane.
• The carbon atoms are numbered from a terminal carbon atom nearest to a carbon atom attached to – OH group so that the position of – OH group is indicated by the lowest locant.
• ‘e’ of an alkane is preplaced by ‘oT, giving alkanol. The number of OH groups is indicated by prefix, di, tri, etc. before ‘oT. The positions of -OH groups are indicated by appropriate locants.
• The different substituents are arranged in the alphabetical order, and their positions are indicated by proper numbers.
• Their names are hyphened on either sides except the last substituent.
• For cyclic alcohols are named by using prefix cyclo to the parent alkane considering – OH group attached to carbon atom C – 1.

Question 8.
Give common and IUPAC names for the following :
Answer:

Question 9.
Classify the following alcohols as primary, secondary and tertiary and write their IUPAC names.
Answer:

Question 10.
Give the structures of the following :
(1) Ethanol
(2) Propan-l-ol
(3) 2-Methylbutan-l-ol
(4) Pentan-3-ol
(5) Butan-2-ol
(6) 3-Methylbutan-2-ol
(7) Hexan-l-ol
(8) 3-Methylpentan-3-ol
(9) 2-Methylpropan-2-ol
(10) Butan-l-ol (H-Butyl alcohol)
(11) 2-Methylpropan-l-ol
(12) 2,3-Dimethylbutan-l-ol
(13) 2, 3-Dimethylbutan-2-oI
(14) 2-MethyIhexan-l-ol
(15) 2,2,3-Trimethylpentan-3-ol
(16) 2,3,3-Trimethylbutan-2-ol
(17) 3-EthyI-4-methylpentan-l-ol.
Answer:

Question 11.
Give the IUPAC names of the following alcohols. Classify them as primary (1°), secondary (2°) and tertiary (3°) alcohols. Identify allylic and benzylic alcohols amongst them.
Answer:

Question 12.
Write all the possible structural isomers of alcohol having molecular formula C6H140. Give their IUPAC names. Classify them as primary, secondary and tertiary alcohols. Identify optically active alcohols amongst them.
Answer:

The optical isomers of C₆H₁₄O are (2), (3), (6), (7), (12).

Question 13.
Give the IUPAC names of the following compounds :
Answer:

Question 14.
Write IUPAC names of following alcohols :
Answer:

Question 15.
Write the structures of following alcohols : (1 mark each)
Answer:

The IUPAC system name of phenol is benzenol. The common name phenol is also accepted by IUPAC. The common names have prefixes ortho, meta and para in substituted phenols. IUPAC system uses the locant 2-, 3-, 4-, etc. to indicate the positions of substituents.

Question 16.
Write the IUPAC names of the following compounds :
Answer:

Question 17.
Write IUPAC name of the following compounds :
Answer:

Question 18.
Give the structures and IUPAC names of isomeric phenols represented by the molecular formula C₈H₁₀O.
Answer:

Common and IUPAC system of nomenclature of ethers

In the common system of nomenclature, the ethers are named by writing names of the alkyl groups attached to the oxygen atom in alphabetical order and word ether is added. If two alkyl groups are same, prefix di- is used. According too the IUPAC system of nomenclature, ethers are named as alkoxyalkanes. The larger alkyl group is considered to be parent alkane. The name of the smaller alkane is prefixed by the name of alkoxy group and its locant.

Question 19.
Give common name and JUPAC name for the I11owing ethers :
Answer:

Question 20.
Give the IUPAC name of the following ethers.
Answer:

Question 23.
Give the structures and IUPAC names of all metameric ethers represented by formula C₅H₁₂O.
Answer:

Question 24.
How many isomeric compounds can be represented by formula C₄H₁₀O?
Answer:
A compound with the molecular formula C₄H₁₀O can show two functional isomers as a monohydric alcohol and ether.

Isomers of C₄H₁₀O as alcohol :

Isomers of C₄H₁₀O as ether :

Hence, the total number of isomers of C₄H₁₀O are seven

Question 25.
Write the structural formula and IUPAC names of all possible isomers of the compound with molecular formula C₃H₈O.
Answer:
Possible isomers of C₃H₈O with structural formulae and IUPAC names :

Question 26.
Write structures of alcoholic and ether isomers of a compound having molecular formula C₇H₈O.
Answer:

Question 27.
How is alkyl halide converted into alcohol by using
(1) Aqueous NaOH (or KOH),
(2) Moist silver oxide?
Answer:
(1) When an alkyl halide (R – X), is boiled with aqueous NaOH (or KOH) an alcohol is obtained,

(2) Alkyl halide when heated with moist Ag₂O, undergoes hydrolysis and forms an alcohol.

Question 28.
How are following compounds prepared by hydrolysis of alkyl halides
(1) Ethanol
(2) Isopropyl alcohol
(3) tert-butyl alcohol
(4) methyl alcohol
(5) butan-2-ol?
Answer:
(1) Ethanol When ethyl bromide (bromoethane) is refluxed with aqueous potassium hydroxide, ethyl alcohol is formed. The reaction is called a hydrolysis reaction.

(2) Isopropyl alcohol : When isopropyl bromide (2-bromopropane) is boiled with aqueous potassium hydroxide, isopropyl alcohol is formed.

(3) Tert-butyl alcohol : When tert-butyl chloride is refluxed with aqueous potassium hydroxide, tert-butyl alcohol is formed.

(4) Methyl alcohol : When methyl bromide (bromomethane) is heated with aq KOH, it is hydrolysed to methyl alcohol (methanol).

(5) Butan-2-ol : When 2-Chlorobutane is boiled with aqueous KOH, Butan-2-ol is obtained.

Question 29.
How are following compounds prepared from alkyl halides using moist silver oxide?
(1) Ethanol
(2) Propan-2-ol.
Answer: ‘
(1) Bromoethane (C₂H₅Br) when boiled with moist Ag₂O undergoes hydrolysis and forms C₂H₅OH.

(2) When 2-chloropropane is boiled with moist Ag20, propan-2-ol is formed.

Question 30.
What is hydration of alkenes or olefins? How is it carried out? Explain with an example.
OR
How are alcohols prepared from alkenes?
Answer:
The addition of a water molecule across the double bond in an alkene is called hydration of alkenes or olefins.

Hydration does not take place directly. It is carried out by passing an alkene through cold and concentrated H₂SO₄ which forms deliquescent solid, alkyl hydrogen sulphate, which when boiled with water forms an alcohol.

Question 31.
How are the following compounds obtained by hydration of alkenes :
(1) Ethyl alcohol
(2) Isopropyl alcohol
(3) Tert-butyl alcohol?
Answer:
(1) When ethene is passed through cold 98 % H₂SO₄, ethyl hydrogen sulphate is formed, which on heating with water gives ethanol.

(2) Propene with cold 80% H₂SO₄ gives isopropyl hydrogen sulphate which further on boiling with water gives isopropyl alcohol.

(3) 2-Methylpropene (isobutylene) directly reacts with 50 % H₂SO₄ giving tert-butyl hydrogen sulphate, which when heated with water gives tert-butyl alcohol.

Question 32.
Identify C in the following reaction.

Answer:

Question 33.
Explain hydroboration-oxidation of alkene.
Answer:
When diborane is treated with alkene in the presence of tetrahydrofuran (THF) solvent, an addition product trialkyl borane is formed. Trialkyl borane is then oxidised with alkaline peroxide forms primary alcohol.

The addition of diborane to the double bond takes place in such a way that the boron gots attached to the less substituted carbon. The overall reaction gives Anti-Markovnikov’s product from unsymmetrical alkenes.

Question 34.
How is propan-l-ol prepared using diborane?
Answer:
When diborane is treated with propene, in the presence of THF an addition product tripropyl borane is formed. Tripropyl borane is then oxidised to propan-l-ol using hydrogen peroxide in the presence of dil NaOH.

The addition of diborane to the double bond takes place in such a way that the boron gets attached to the less substituted carbon. The alcohol formed by the addition of water to the alkene in a way opposite to the Markovnikov’s rule.

Question 35.
How is ethanol prepared using diborane?
Answer:
When diborane is treated with ethene in the presence of THF an addition product triethylborane is formed.Triethylborane is then oxidised with hydrogen peroxide to form ethyl alcohol.

Question 36.
Predict the major product when 2-methylbut-2-ene is converted into an alcohol in each of the following methods :
(1) acid catalysed hydration
(2) hydroboration by BH₃ – THF complex.
Answer:
(1) Acid catalysed hydration :

(2) Hydroboration by BH₃ – THF complex :

Question 37.
How are alcohols prepared from aldehydes and ketones?
OR
How are the following compounds obtained using Ni as catalyst and at high temperature
(1) Ethanol
(2) Propan-2-ol?
Answer:
Aldehyde and ketones are carbonyl compounds containing a carbonyl group  C = O. The reduction of the carbonyl group gives an alcohol.

(1) Primary alcohols are prepared by the reduction of aldehydes.

Example : When acetaldehyde is reduced with hydrogen in the presence of nickel as catalyst and at high temperature, ethyl alcohol (ethanol) is obtained.

(2) Secondary alcohols are prepared by the reduction of ketones.

Example : When acetone is reduced with hydrogen in the presence of nickel as catalyst and at high temperature, isopropyl alcohol (propan-2-ol) is obtained.

Question 38.
How will you convert carboxylic acids and esters to primary alcohols? Explain with suitable examples.
Answer:
Carboxylic acids and esters are not easily reduced by catalytic hydrogenation or by NaBH₄. However, relatively more reactive and an expensive LiAlH₄ is used to convert carboxylic acids and esters to primary alcohols. When acetic acid is reduced in the presence of LiAlH₄ and followed by their acid hydrolysis, ethyl alcohol is obtained.

When ethyl acetate is reduced in the presence of LiA1H₄ and followed by their acid hydrolysis. n-propyl alcohol and ethyl alcohol is obtained.

[Since LiA1H₄ is an expensive reagent. commercially acids are reduced to alcohol by converting them to esters, followed by their reduction. (catalytic hydrogenation)

Question 39.
How is Crotoflyl alcohol obtained from crotonaldehyde?
Answer:
When crotonaldehyde is reduced in the presence of lithium aluminium hydride, the produc obtained is hydrolysed to give crotonyl alcohol. Here. LiA1H₄ does not reduce carbon-carbon double bond.

Question 40.
WrIte the structure of aldehyde that yields

Answer:
The structure of aldehyde:

Question 41.
How are the following compounds prepared using Grignard reagent
(1) Ethanol
(2) Propan-l-ol
(3) Propan-2-ol
(4) 2-Methyl propan-2-ol?|
Answer:
(1) Ethanol : Formaldehyde on reaction with Grignard reagent, CH₃ – Mg – I in dry ether forms a complex which on further hydrolysis with dilute HCl forms ethanol.

(2) Propanol-l-ol : Formaldehyde on reaction with Grignard reagent, C₂H₅ – Mg – I in dry ether forms a complex which on further hydrolysis with dilute HC1 forms Propan-l-ol.

(3) Propan-2-ol : An acetaldehyde on reaction with Grignard reagent in dry ether forms a complex which on further hydrolysis with dilute acid HC1, forms propan-2-ol.

(4) 2-Methyl propan-2-ol : Acetone on reaction with Grignard reagent in dry ether forms a complex which on further hydrolysis with dilute acid HCl, forms a tertiary butyl alcohol.

Question 42.
Give a mechanism of following reaction.

Answer:
Grignand reagent reacts with aldehyde or ketone to form an adduct which on hydrolysis with dil. acid gives the corresponding alcohol.

In the first step, the nucleophilic addition of Grigard reagent to the carbonyl group resulting in the formation of an adduct, which on hydrolysis yields an alcohol.

Question 43.
Write the structure of carbonyl compounds that can be converted by reduction methods into following alcohols :


Answer:

Answer:

Question 44.
Using Grignard reagent, suggest synthesis of following alcohols from aldehydes or ketones. Wherever possible, suggest more than one combination.

Answer:

(b) Synthesis of propan- 1-01:

(c) Synthesis of butan-2-ol:

(d) Synthesis of 2-methylhexan-2-oI:

Question 45.
How will you obtain butan-2-ol from
(1) Propanal
(2) butan-2-one
(3) but-2-ene?
Answer:
(1) Propanal : When propanal is treated with methyl magnesium iodide in the presence of dry ether, a complex is formed, which on acid hydrolysis butan 2-ol is obtained.

(2) Butan-2-one: When butan-2-one is hydrogenated at 413 K in the presence of catalyst finely divided nickel butan-2-ol is obtained.

(3) But-2-ene : When but-2-ene is passed through cold concentrated sulphuric acid, isobutyl hydrogen sulphate is formed. Isobutyl hydrogen sulphate on heating with water gives butan-2-ol.

Question 46.
Write the structure of aldehyde, carboxylic acid and ester that yield the following alcohol.

Answer:

Question 47.
How will you prepare?
(1) 2-Ntethylbutan-1-oI from an alkene.
Answer:

(2) CycIoheyImethanoI from a Grignard reagent.
Answer:

(3) 1-Phenyl ethanol from acelaldehyde.
Answer:

Question 48.
How are following conversions brought about?
(1) Benzyl chloride to benzyl alcohol. (NCERT)
OR
How is benzyl alcohol prepared from benzyl chloride?
Answer:

(2) Benzyl alcohol to Benzoic acid.
Answer:

(3) 1-Ethyl cyclohexanol from cyclohexanone.
Answer:

Question 49.
How is phenol (carbolic acid) prepared from chlorobenzene (Dow’s process)? OR
Write chemical reaction for the preparation of phenol from chlorobenzene.
Answer:
Preparation of phenol from chlorobenzene (Dow’s process) : Chlorobenzene is fused with NaOH at about 623 K under a pressure of about 150 atmospheres (1.5 x 10⁷ Nm^-2), when sodium phenoxide is formed. Sodium phenoxide is acidified with dil.HCl to obtain phenol.

Question 51.
How is phenol (carbolic acid) prepared from benzene sulphonic acid?
Answer:
Preparation of phenol from benzene sulphonic acid : Benzene sulphonic acid is neutralized with the requisite quantity of soda ash (Na₂CO₃) or NaOH and the solution is evaporated to obtain sodium benzene sulphonate salt. Dry sodium benzene sulphonate is fused with an excess of caustic soda (NaOH) at about 573 K when sodium phenoxide is formed. The fused mass of sodium phenoxide on treatment with dilute HC1 gives phenol.

Question 52.
How is phenol (carbolic acid) prepared from aniline (diazotization)?
OR
How is carbolic acid prepared from amino benzene?
Answer:
Preparation of phenol from aniline (diazotization) : When aniline is treated with sodium nitrite and hydrochloric acid (NaNO₂ + HC1) at low temperature (0°C – 5°C), benzene diazonium chloride is formed. This reaction is called diazotization. An aqueous solution of benzene diazonium chloride on warming with water or dil. H2S04 gives phenol.

Question 54.
Describe the physical properties of alcohols and phenols.
Answer:
The properties of alcohols and phenols are mainly due to the hydroxyl group.

(1) Nature of intermolecular forces : Due to presence of – OH groups, alcohols and phenols are polar molecules. The polar – OH groups are held together by the strong intermolecular forces i.e. hydrogen bonding.

(2) Physical State : Lower alcohols are colourless, toxic liquids having characteristic alcoholic odour. Pure phenol is colourless, toxic, low melting solid having characteristic carbolic or phenolic odour.

(3) Boiling Points : The boiling points of alcohols and phenols increase with increase in their molecular mass.
Methyl alcohol – 65 °C
Phenol -182° C
n-Butyl alcohol-118 °C
o-nitrophenol-217 °C

(4) Solubility : Solubility of alcohols and phenols in water due to their ability to form intermolecular hydrogen bonding.

Question 55.
Arrange the following compounds in order of their increasing boiling points.
Butan-2-ol, ethanol, pentan-l-ol, butan -l-ol, propan-l-ol, methanol.
Answer:
Methanol, ethanol, propan:l-ol, butan-2-ol, butan-1 -ol pentan-l-ol.

Question 56.
Explain the following :
(1) Ethanol has higher boiling point than ethane.
Answer:
(1) The hydroxyl group in alcohols is highly polar. The H-atom has partial positive charge and the oxygen atom has partial -ve charge. The hydroxyl group in ethanol is extensively hydrogen bonded.

(2) Large number of ethanol molecules associated together by intermolecular hydrogen bonding. The energy required to separate the molecules by breaking hydrogen bond into vapour state is higher. This results in increasing the boiling point of ethanol.

(3) On the other hand, in ethane (alkane) there is no hydrogen bonding between the molecules. The molecules of ethane are held together by weak van der Waals forces of attraction. Hence, these molecules can be easily separated. Thus, ethanol has higher boiling point than that of ethane.

(2) Methanol is more soluble in water than propan-l-ol.
Answer:
(1) Methanol being lower members of alcohols is more soluble in water, but as the size of an alkyl group or molecular weight of alcohol increases the solubility decreases.

(2) The solubility of methanol in water is due to polar characters of alcohols (R – O^-δ -H^+δ ) and water (H^+δ – O^-δ – H^+δ).

(3) The solubility of methanol is due to the formation of intermolecular hydrogen bonding between polar molecules of methyl alcohol and water. Hence, methyl alcohol is a associated liquid.

(4) In methyl alcohol, size of methyl group being very small, -OH group constitutes major part of the molecule giving more solubility. As size of alkyl group increases, the non-polar character increases the solubility decreases. Hence, methanol is more soluble in water than propan-l-ol.

Question 57.
Which of the following pair is more acidic and why?

Answer:
Due to high electronegativity of sp²-hybridized carbon, electron density on oxygen in phenol (I) decreases. This increases the polarity of O – H bond and results in more ionization of phenol than that of cyclohexyl alcohol (II). Therefore, phenol is more acidic than cyclohexyl alcohol.

Answer:
In p-nitrophenol, nitro group (N02) is an electron-withdrawing group present at ortho position which enhances the acidic strength (- I effect). The O – H bond is under strain and release of proton (H⁺) becomes easily. Hence, o-nitrophenol is more acidic than phenol.

Question 58.
Draw intramolecular hydrogen bonding structures in the following compounds :
(a) o-nitrophenol
(b) o-hydroxy benzoic acid.
Answer:
(a) o-nitrophenol :

(b) o-hydroxy benzoic acid :

Question 59.
Explain laboratory test of alcohols and phenols.
Answer:
Laboratory test : Aqueous solution of alcohols and phenols can be tested with litmus paper. Aqueous solution of alcohols is neutral to litmus (neither blue nor red litmus change colour). Aqueous solutions of phenols turn blue litmus red. Thus, phenols have acidic character.

Question 62.
Write the action of aq NaOH on phenol and the product obtained is acidified.
Answer:
Phenols dissolve in aqueous NaOH by forming water soluble sodium phenoxide and are reprecipitated/ regenerated as phenols on acidification with HC1.

Question 63.
Explain the action of sodium on ethanol.
Answer:
When cthanol is treated with sodium metal, sodium ethoxide is formed and hydrogen gas is liberated.

Liberation of H₂ gas is used to detect the presence of alcoholic -OH group of a molecule.

Question 64.
How are the following compounds obtained from alcohols using HCI:
(1) C₂H₅CI
(2) Isopropyl chloride
(3) tert-butyl chloride?
Answer:
(1) Ethyl alcohol, C2H5OH in the presence of Lucas reagent (ZnCl₂ + HCI conc.) forms ethyl chloride.

(2) Isopropyl alcohol reacts with Lucas reagent forms isopropyl chloride.

(3) Tert-butyl alcohol reacts with Lucas reagent forms tert-butyl chloride

Question 65.
What is Lucas reagent? What are its uses?
Answer:
Lucas reagent is composed of a mixture of concentrated HCl and Lewis acid. anhydrous ZnCI₂.

It is used to prepare alkyl chlorides and distinguish between 10, 2° and 3° alcohols.

Question 66.
How can alcohols be distinguished with the help of Lucas reagent?
Answer:
Lucas reagent is a mixture of concentrated HCI and anhydrous ZnCl₂. It is used to distinguish between primary, secondary and tertiary alcohols.
Alcohol with Lucas reagent forms an alkyl chloride, R -Cl which is insoluble and gives cloudiness and forms separate layer.

The time required for cloudiness to appear is based on the type of the alcohol and its reactivity :

(1) Primary alcohol : It reacts with the Lucas reagent very slowly and on heating forms alkyl chloride. The cloudiness and separation of a layer takes place after a long time on heating.

(2) Secondary alcohol : It reacts with the Lucas reagent much faster to form alkyl chloride. The cloudiness and separation of layer takes place slowly.

(3) Tertiary alcohol : It reacts immediately with the Lucas reagent at room temperature to form alkyl chloride. The cloudiness and separation of layer takes place instantaneously.

Question 67.
What is esterificatlon? how Is an ester obtained from alcohol or phenol?
Answer:
(1) When an alcohol or phenol is heated with a carboxylic acid in the presence of conc.sulphuric acid an ester is obtained. The reaction is called esterification. This is reversible reaction and the formation of an ester is favoured
using excess of alcohol in the presence of conc. H₂SO₄.

(2) Alcohols and phenols react with acid anhydrides in presence of acid catalyst to form eser.

(3) The reaction of alcohol and phenols with acid chloride is carried out in the presence of pyridine (base), which neutralizes HCl.

Question 68.
Explain the action of the following on ethanol :
(1) Acetic acid
(2) Acetic anhydride
(3) Acetyl chloride.
Answer:
(1) Acetic acid : When ethanol is treated with acetic acid in the presence of cone, sulphuric acid, ethyl acetate (ester) is formed.

(2) Acetic anhydride : When ethanol is treated with acetic anhydride in the presence of cone, sulphuric acid, ethyl acetate (ester) is formed.

(3) Acetyl chloride : When ethanol is treated with acetyl chloride in the presence of pyridine, ethyl acetate (ester) is formed.

(Pyridine neutralises HC1 formed during reaction)

Question 69.
Explain the action of the following phenol :
(1) Acetic acid
(2) Acetic anhydride
(3) Acetyl chloride
Answer:
(1) Acetic acid : When phenol is treated with acetic acid in the presence of cone, sulphuric acid, (ester) is formed.

(2) Acetic anhydride : When phenol is treated with acetic anhydride in the presence of cone, sulphuric acid, (ester) is formed.

(3) Acetyl chloride : When phenol is treated with acetyl chloride in the presence of cone, sulphuric acid, (ester) is formed.

(Pyridine neutralizes HC1 formed during reaction.)

Question 70.
What is the action of acetic anhydride on salicyclic acid?
Answer:
When acetic anhydride is treated with salicyclic acid in presence of glacial acetic acid, acetyl salicyclic acid (aspirin) is obtained.

Aspirin is a common analgesic, antipyretic drug. Reactions involving breaking of C – O bond of alcohol :

Question 71.
How are the following compounds prepared by using HBr from corresponding alcohols :
(1) Ethyl bromide
(2) Isopropyl bromide
(3) Tert-butyl bromide (2-Methyl-propan-2-ol)?
Answer:
(1) When ethyl alcohol is heated with HBr, ethyl bromide is formed. (HBr is prepared in situ by adding NaBr to HCl or H₂SO₄)

(2) Isopropyl alcohol on heating with HBr forms isopropyl bromide.

(3) Tert-butyl alcohol on heating with HBr forms tert-butyl bromide.

Question 72.
Explain the action of hydroiodic acid on the following :
(1) Propan-2-ol
(2) 3-Methyl butan-2-ol.
Answer:
(1) Propan-2-ol : When propan-2-ol is heated with hydroiodic acid, 2-iodopropane is formed.

(2) 3-Methyl butan-2-ol : When 3-Methyl butan-2-ol is heated with hydroiodic acid, 2-Iodo-2-methyl butane is obtained. Here, secondary alcohol is converted into a tertiary alkyl halide.

Question 73.
Describe the action of PCl₃ on
(1) ethanol
(2) Propan-l-ol
(3) Propan-2-ol.
Answer:
(1) Ethanol : When ethanol is treated with PCl₃, ethyl chloride is obtained.

(2) Propan-l-ol : When propan-l-ol is treated with PCl₃, n-propyl chloride is obtained.

(3) Propan-2-ol : When Propan-2-ol is treated with PCl₃, 2-Chloropropane is obtained.

Question 74.
Describe the action of PCl₅ on
(1) ethanol
(2) propan-2-ol.
Answer:
(1) Ethanol : When ethanol is treated with PCl₅, ethyl chloride is obtained.

(2) Propan-2-ol : When propan-2-ol is treated with PCl₅, 2-chloropropane is obtained.

Question 75.
Describe the action of SOCl₂ on
(1) ethanol
(2) propan-l-ol.
Answer:
(1) Ethanol : When ethanol is treated with SOCl₂ in the presence of pyridine, ethyl chloride is obtained.

(2) Propan-l-ol : When propan-l-ol is treated with SOCl₂ in the presence of pyridine, w-propyl chloride is obtained.

Question 76.
Explain dehydration of alcohols.
OR
What is dehydration of alcohols? Give the chemical reactions showing dehydration of primary (1°), secondary (2°) and tertiary (3°) alcohols.
Answer:
Removal of water from an alcohol is called dehydration of alcohol. Alcohols having a /i-hydrogen is heated with dehydrating agents like concentrated H₂SO₄ (or H₃PO₄ or P₂O₅ or Al₂O₃). The ease of dehydration of alcohols is in the following order : tert-alcohol (3°) > secondary (2°) > primary (1°)
(1) Primary (1°) alcohol is dehydrated by heating it with 95% H₂SO₄ at 453 K.

(2) Secondary alcohol (2°) is dehydrated by heating with 60% H₂SO₄ at 373 K.

(3) A ternary alcohol can be easily dehydrated by heating with 20% H₂SO₄ at 363 K.

An alcohol can be dehydrated by passing vapours alcohols over heated alumina (Al₂O₃).

Question 77.
Explain oxidation of primary and secondary alcohols.
Answer:
(1) Primary alcohol on oxidation with CrO₃ forms aldehyde. However, a better reagent to bring about this oxidation is PCC (pyridinium chlorochromate).

(2) Secondary alcohol on oxidation with chromic anhydride (CrO₃) forms ketone.

Question 78.
What is the action of acidified K₂Cr₂O₇ on the following :

How are following alcohols distinguished :
(1) ethyl alcohol
(2) isopropyl alcohol
(3) tert-butyl alcohol?
OR
How will you distinguish primary, secondary and tertiary alcohols by oxidation process?
Answer:
Primary, secondary and tertiary alcohols are distinguished on the basis of their oxidation products, when their oxidation is carried out using K₂Cr₂O₇ and dil. H₂SO₄. Acidified potassium dichromate, K₂Cr₂O₇ is an oxidising agent.

(1) Ethyl alcohol is a primary alcohol and on oxidation, it first forms acetaldehyde, which on further oxidation forms acetic acid. In this both, aldehyde and acid have same number of carbon atoms.

(2) Isopropyl alcohol is a secondary alcohol and on oxidation it gives a ketone, acetone with the same number of carbon atoms. Acetone resists further oxidation as it involves breaking of C-C bond.

(3) The oxidation of tert-butyl alcohol is difficult, since it does not have a-hydrogen atom. It is oxidised by using acidic and stronger oxidising agents like KMn04, CrO₃ at high temperature, which dehydrate tertiary alcohol to alkene and then oxidise it to a ketone, acetone with less number of carbon atoms.

Question 79.
What happens when vapours of primary, secondary and tertiary alcohols are passed over heated copper at 573 K?
Answer:
When vapours of primary, secondary and tertiary alcohols are passed over heated copper at 573 K, dehydrogena¬tion of primary and secondary alcohol takes place while tertiary alcohols undergo dehydrogenation to given an alkene.

Primary alcohol :

Secondary alcohol :

Reactions of phenols :

Question 80.
(1) Explain the action of bromine in carbon disulphide (CS₂) on phenol (carbolic acid). OR Give equation of the reaction of bromine in CS₂ with phenol.
Answer:
When phenol is stirred at a low temperature with bromine dissolved in a polar solvent such as carbon disulphide or CCl₄ at (273 K), a mixture of o-bromophenol and p-bromophenol is formed, p-bromophenol is the major product.

Question 81.
Explain the action of bromine water on phenol (carbolic acid).
OR
Name the reagent used in the bromiriation of phenol to 2, 4, 6 tribromophenol.
Answer:
When phenol is treated with bromine water, a yellowish white precipitate of 2, 4, 6 – tribromophenol is formed.

Question 82.
Explain the action of dilute nitric acid on phenol (carbolic acid).
OR
Give equation of the reaction of dilute HNO₃ with phenol.
Answer:
When phenol is treated with dilute nitric acid, a mixture of o-nitrophenol and p-nitrophenol is formed. In this reaction, p-nitrophenol is formed as the major product.

Question 83.
Explain the action of cone, nitric acid (nitrating mixture) on phenol (carbolic acid).
OR
How is phenol converted into picric acid?
Answer:
When phenol is warmed with a mixture of cone, nitric acid and cone, sulphuric acid (a nitrating mixture or the mixed acid), 2, 4, 6 – trinitrophenol, commonly called picric acid, is formed.

Question 84.
Explain the action of concentrated sulphuric acid on phenol at different temperatures.
Answer:
(a) At room temperature : When phenol is treated with cone. H₂SO₄ at room temperature (about 300 K), o-phenol sulphonic acid is formed.

(b) At 373 K : When phenol is treated with cone. H₂SO₄ at about 373 K, p-phenol sulphonic acid is formed.

Question 85.
Explain (1) Kolbe’s reaction (2) Reimer-Tiemann reaction.
Answer:
(1) Kolbe’s reaction : When phenol reacts with sodium hydroxide, sodium phenoxide is obtained. Phenoxide ion being more reactive than phenol towards electrophilic substitution. Phenoxide undergoes electrophilic substitution with carbon dioxide at 398 K under pressure of 6 atm (a weak electrophile) forms salicylic acid as major product.

(2) Reimer-Tiemann reaction : Phenol is heated with chloroform along with aqueous NaOH, this is followed by acidification with dil. HC1 when salicyladehyde (2-hydroxy benzaldehyde) is formed as the major product, which can be separated from p-isomer by steam distillation. The stability of o-isomer is due to intramolecular hydrogen bonding.

Question 86.
Explain the action of zinc dust on phenol.
OR
How is phenol converted into benzene?
Answer:
When phenol is heated with zinc dust, benzene is obtained.

Question 87.
Explain the action of chromic acid on phenol.
OR
How is phenol converted into benzoquinone?
Answer:
When phenol is oxidised by chromic acid, a diketone, p-benzoquinone is formed. It is a conjugated diketone.

Question 88.
Explain catalytic hydrogenation of phenol.
Answer:
When a mixture of vapours of phenol and hydrogen is passed over nickel catalyst at 433 K., cyclohexanol is obtained.

Question 89.
How is diethyl ether (ethoxyethane) obtained from alcohol?
Answer:
When excess of ethyl alcohol is distilled with concentrated sulphuric acid (H₂SO₄) at 413 K, diethyl ether is formed.

Question 91.
Write a note on Williamson’s synthesis.
OR
How are ethers prepared from Alkyl halides?
OR
How are simple ethers and mixed ethers prepared by Williamson’s synthesis?
Answer:
Williamson’s synthesis : When an alkyl halide (R – X) is heated with sodium alkoxide (R – O – Na), an ether is obtained, this reaction is known as Williamson’s synthesis. This method is used to prepare simple (or symmetrical) ethers and mixed (unsymmetrical) ethers.

Sodium alkoxide is obtained by a reaction of sodium with an alcohol.

(A) Simple (Symmetrical) ether : When an alkyl halide and sodium alkoxide having similar alkyl groups are heated, symmetrical ether is obtained.

Sodium ethoxide on heating with ethyl bromide gives diethyl ether.

(B) Mixed (Unsymmetrical) ether : When an alkyl halide and sodium alkoxide or sodium phenoxide having different alkyl groups are heated, unsymmetrical ether (dialkyl ethers or alkyl aryl ether) is obtained.

Sodium ethoxide on heating with methyl bromide gives ethyl methyl ether.

Sodium phenoxide on heating with ethyl bromide gives ethyl phenyl ether.

Question 92.
How is anisole obtained from phenol?
OR
How is methoxy benzene prepared from carbolic acid?
Answer:
Phenol reacts with sodium hydroxide, sodium phenoxide is formed. When sodium phenoxide is heated with methyl iodide, anisole is obtained.

Question 93.
Explain the limitations for the preparation of unsymmetrical ethers.
OR
What care is to be taken in the preparation of unsymmetrical ethers by Williamson’s synthesis? Explain.
OR
Illustrate with examples the limitations of Williamson’s synthesis for the preparation of certain types of ethers.
Answer:
(1) In the preparation of unsymmetrical ethers by Williamson’s synthesis, the proper choice of the reactants namely alkyl halide and sodium alkoxide is necessary.

(2) The best yield of unsymmetrical ether is obtained when primary alkyl halide and tertiary alkoxide are heated, since primary alkyl halides are more susceptible to SN² reaction.

(3) Secondary or tertiary alkyl halide undergo a and fi (halogen and hydrogen) elimination reaction giving an alkene instead of an ether since a carbon atom is sterically hindered by bulky alkyl groups.

(4) For example : t-butyl methyl ether can be synthesised by reaction of methyl bromide with sodium t-butoxide.

Question 94.
State physical properties of ethers.
Answer:
(1) Dimethyl ether and ethyl methyl ether are gases. Other ethers are colourless liquids with pleasant odour.
(2) Lower ethers are highly volatile and highly inflammable substances.
(3) Boiling points of ethers show gradual increase with the increase in molecular mass.

(4) The solubility/miscibility of ethers in water is similar to that of alcohols of comparable molecular mass.

Question 95.
Explain, ethers posses a small net dipole moment.
Answer:
In ethers, bond angle is 110° and not 180°, bond dipole moments of the two C – O bonds do not cancel each other, therefore, ethers possess a smal net dipole moment, (for example, dipole moment of diethyl ether is 1.18 D)

Question 96.
Explain, the solubility/miscibility of ethers in water is similar to that of alcohols of comparable molecular mass.
Answer:
The solubility/miscibility of ethers in water is similar to that of alcohols of comparable molecular mass. This is because ethers can form hydrogen bonds with water through ethereal oxygen.

For example, diethyl ether and n-butyl alcohol have respective miscibilities of 7.5 and 9 g per 100 g of water.

Question 97.
Explain laboratory test for ethers.
Answer:
Ethers are neutral compounds in aqueous medium. Ethers do not react with bases, cold dilute acids, reducing agents, oxidizing agents and active metals. However, ethers dissolve in cold concentrated H₂SO₄ due to formation of oxonium salts.

This property distinguishes ethers from hydrocarbons.

Question 98.
What is the action of atmospheric oxygen on diethyl ether?
Answer:
When atmospheric oxygen combines with diethyl ether, peroxide of diethyl ether is obtained.

Question 99.
What is the action of dilute sulphuric acid on
(1) Dimethyl ether
(2) Diethyl ether
(3) Ethyl methyl ether?
(4) Anisole?
OR
Explain hydrolysis of ethers.
Answer:
Simple ethers on heating with dilute sulphuric acid under pressure undergoes hydrolysis to give alcohol.

(1) Dimethyl hydrolysis on hydrolysis give methanol.

(2) Diethyl ether on hydrolysis give ethanol.

(3) A mixed ether on heating with dii. H₂SO₄ under pressure undergoes hydrolysis to give mixture of two different alcohols.

Ethyl methyl ether on hydrolysis give a mixture of ethanol and methanol.

(4) Anisole on hydrolysis give a mixture of phenol and methanol.

Question 100.
State the combustion products of diethyl ether.
Answer:
The combustion products of diethyl ether are CO₂ and H₂O.

Question 101.
What is the action of phosphorus pentachloride on
(1) Diethyl ether
(2) Ethyl methyl ether
(3) Methyl phenyl ether (anisole)?
Answer:
(1) Diethyl ether : When diethyl ether is heated with ethyl methyl ether, ethyl chloride is formed.

(2) Ethyl methyl ether : When ethyl methyl ether is heated with phosphorus pentachloride, a mixture of ethyl chloride and methyl chloride is formed.

(3) Methyl phenyl ether (Anisole) : When methyl phenyl ether is heated with phosphorus pentachloride, a mixture of methyl chloride, chlorobenzene is formed.

Question 102.
Describe the action of hot concentrated HI on
(i) Dialkyl ether
(ii) Alkyl aryl ether.
Answer:
Ether reacts with excess of hot concentrated hydrogen halide to give two alkyl halide molecules.
R – O – R + HX → RX + R – OH
R – OH + HX → RX + H₂0
Alkyl aryl ether reacts with hot concentrated hydrogen halide to give phenol and alkyl halide.

Ethers with two different alkyl groups react with hot.conc. HI to give alkyl halides.
R – O – R’+ 2H – X → R – X + R’ – X + H₂O
The order of reactivity of HX is HI > HBr > HC1

Question 103.
What is the action of hot HI on isopropyl methyl ether?
Answer:
When isopropyl methyl ether is treated with excess of hot hydroiodic acid, a mixture of isopropyl iodide and methyl iodide is formed.

Question 104.
Describe the action of hydroiodic acid on the following :
(1) Diethyl ether.
Answer:
When diethyl ether (ethoxy ethane) is treated with hydroiodic acid, a mixture of ethanol and ethyl iodide is formed.

If excess of hydroiodic acid is available, then ethyl alcohol further reacts with hydroiodic acid at higher temperature to form ethyl iodide and water.

(2) Ethyl methyl ether.
Answer:
When ethyl methyl (methoxy ethane) is treated with hydroiodic acid, a mixture of ethyl alcohol and methyl iodide is formed.

If excess of hydroiodic acid is available, then ethyl alcohol further reacts with hydroiodic acid at higher temperature to form ethyl iodide and water.

(3) Methyl n-propyl ether.
Answer:
When methyl n-propyl ether (1-Methoxy propane) is treated with hydroiodic acid, a mixture of n-propyl alcohol and methyl iodide is formed.

If excess of hydroiodic acid is available then n-propyl alcohol further reacts with hydroiodic acid at higher temperature to form n-propyl iodide and water.

(4) Methyl phenyl ether (anisole).
Answer:
When methyl phenyl ether (anisole) is treated with hydroiodic acid, phenol and methyl iodide is formed. Here, phenol does not react further with HI because – OH group is attached to sp²-hybridised carbon atom and it cannot be replaced by iodide (nucleophile).

Question 105.
Draw the resonance structures of aromatic ethers.
Answer:
The alkoxy group in aromatic ether is a ring activating and ortho-, paradirecting group toward electrophilic aromatic substitution.

Resonance structures :

+ R Effect of – OR group results in increased electron density at the para- and two ortho-posotions (see resonance structures II, III and IV).

Question 106.
Describe the action of bromine in acetic acid on anisole.
OR
Write the equation of the reaction of bromination of anisole in ethanoic acid medium.
Answer:
When anisole is treated with bromine in acetic acid, /i-bromoanisole (major product) is obtained.

Question 107.
Describe the action of methyl chloride on anisole (Friedel-Crafts reaction).
OR
Write the equation of Friedel-Crafts reaction-alkylation of anisole.
Answer:
When anisole is treated with alkyl halide in the presence of anhydrous aluminium chloride (a Lewis acid) as catalyst, 4-Methoxy toluene is formed as major product. The alkyl groups are introduced at -ortho and -para positions in anisole, the reaction is known as Friedel-Crafts alkylation reaction.

Question 108.
Describe the action of Acetyl chloride on anisole (Friedel-Crafts acylation).
OR
Write the equation of the reaction Friedel-Crafts acylation of anisole.
OR
Write a note on Friedel-Crafts acylation.
Answer:
When anisole is treated with acetyl chloride in the presence of anhydrous aluminium chloride (a Lewis acid), 4-Methoxy acetophenone (major product) is obtained. The acetyl groups are introduced at -ortho and -para positions in anisole, the reaction is known as Friedel Craft’s acylation reaction.

Question 109.
Describe the action of cone. HNO₃ on anisole.
OR
Write the equation of nitration of anisole.
Answer:
When anisole is reacted with nitrating mixture (cone. HNO₃ + cone. Fl₂SO₄), a mixture of p-nitroanisole and o-nitroanisole is obtained.

Question 110.
An organic compound with the formula C₄H₁₀O₃ shows properties of ether and alcohol. When treated with an excess of HBr yields only one compound 1,2 dibromomethane. Write structural formula of ether and that of alcohol.
Answer:
When C₄H₁₀O₃ is treated with excess of HBr, a single compound 1,2-dibromoethane is formed.

Question 111.
An organic compound ‘A’ having molecular formula C₄H₁₀O does not react with sodium metal. On hydrolysis with dilute H₂SO₄ it gives only one organic compound ‘B’ The compound B on heating with red phosphorus and iodine gives compound ‘C’. The compound C can also be obtained from compound ‘A’ on heating with excess HI. Identify the compounds A, B and C.
Answer:
(1) The organic compound ‘A’ with molecular formula C₄H₁₀O may be an alcohol or ether.

(2) Since ‘A’ does not react with sodium (Na), it is not an alcohol. Hence ‘A’ may be an ether.
(3) Since an ether ‘A’ on hydrolysis with dilute H₂SO₄ gives only one compound ‘B’, the compound ‘A’ must be a symmetrical (simple) ether. Hence compound ‘A’ may be, C₂H₅ – O – C₂H₅

Question 112.
How will you affect the following two-step conversions? Diethyl ether into n-butane :
Answer:

Question 114.
Answer in one sentence/word.

(1) Name the alcohol that is used to make propan-2-one.
Answer:
The alcohol used to make propan-2-one is iso-propyl alcohol.

(2) Which is the first oxidation product of secondary alcohol?
Answer:
The first oxidation product of secondary alcohol is ketone.

(3) Name the alcohol that is used to make acetic acid.
Answer:
The alcohol that is used to make acetic acid is ethyl alcohol.

(4) Write the structure of cyclohexane-1, 4-diol.
Answer:

(9) Which of the following isomers is more volatile : o-nitrophenol or p-nitrophenol?
Answer:
The isomer o-nitrophenol with lower boiling point is more volatile.

(10) Identify the product of the following reaction.

Answer:

(11) Identify the product obtained by industrial synthesis of carboxylation of phenoxide ion followed by acidification.
Answer:
The product is phenol

(12) What is the product A obtained in the following reaction?

Answer:
The product is phenol

(13) Which positions are occupied by – NO₂ group during nitration of carbolic acid?
Answer:
– o – (ortho) and – p – (para) positions are occupied by – NO₂ group during nitration of carbolic acid.

(14) Write the name of reactants used for the preparation of ethyl-tert-butyl ether.
Answer:

are used for the preparation of ethyl-tert-butyl ether.

(15) The product formed in the reaction of reverse of dehydration of alcohol is
Answer:
The product formed in the reaction of reverse of dehydration of alcohol is alkene.

(16) Which rule is obeyed by hydroboration oxidation process?
Answer:
The rule obeyed by hydroboration oxidation process is opposite to the Markovnikov’s rule.

(17) Name the reagents for the complete hydroboration-oxidation reaction in step 1 and step 2.
Answer:
Step 1 : Diborane
Step 2 : Hydrogen peroxide and dil. NaOH.

(18) Write the name of the test by which methanol can be distinguished from ethanol.
Answer:
Iodoform test by which methanol can be distinguished from ethanol.

(19) Write the name of reactant used for preparation of phenol, which gives byproduct used as solvent.
Answer:
Reactant used in the preparation of phenol :

(20) Ether is a good solvent for Grignard reagent. Which property makes it a good solvent?
Answer:
Ether has a low polarity, this property makes it a good solvent.

(21) The C – O – C bond angle in dimethyl ether is
Answer:
The C – O – C bond angle in dimethyl ether is 110°.

Question 115.
State the uses of methyl alcohol.
Answer:
(1) Methyl alcohol is used as an industrial solvent for dissolving oils, fats, gums, etc.
(2) It is used for dry cleaning and preparation of perfumes and varnishes.
(3) It is used as antifreeze agent for automobile radiators at low temperature.
(4) It is used in the preparation of methyl chloride, dimethyl sulphate and formaldehyde.
(5) It is used to denature ethyl alcohol.

Question 116.
State the uses of ethyl alcohol. OR Write two uses of ethyl alcohol.
Answer:
(1) Ethyl alcohol is used as solvent for dyes, oils, perfumes, cosmetics and drugs.
(2) A mixture of 10-20% ethyl alcohol with petrol is used as motor fuel.
(3) A mixture of ethyl alcohol and calcium acetate in gel form is used as solid fuel.
(4) It is widely used in beverages.
(5) Since ethyl alcohol has low freezing point, it is used in thermometer.
(6) It is an effective tropical antiseptic therefore it is used in many mouth washes.
(7) It kills micro-organisms on wound surface and in the mouth but its low toxicity does not kill the cells of the skin or mouth tissues.
(8) It is used in the preparation of chloroform, iodoform, acetic acid and ethers.
(9) It is used as fuel.

Question 117.
Give the important uses of phenol.
OR
Write two uses of phenol.
Answer:
(1) Phenol is used in the preparation of phenol-formaldehyde polymer which is used in a plastic bakelite.
(2) It is used in the preparation of phenol-phthalein-an indicator and in certain dyes.
(3) It is used in the preparation of drugs such as salol, aspirin, etc.
(4) It is used in the preparation of dettol, which is an antiseptic.
(5) It is used in the preparation of 2,4-dichlorophenoxy acetic acid which is used as selective weed killer.
(6) It is used to prepare picric acid which is used as explosive.

Multiple Choice Questions

Question 118.
Select and write the most appropriate answer from the given alternatives for each sub-question:

1. Which one of the following is a tertiary alcohol?
(a) Pentan-l-ol
(b) Pentan-2-ol
(c) 2-Methylpentan-2-ol
(d) 3-Methylpentan-2-ol
Answer:
(c) 2-Methylpentan-2-ol

2. Which of the following is a primary alcohol?
(a) 3-ethyl-3-hexanol
(b) 2-butanol
(c) 3-methyl-l-butanol
(d) 1-hexanol
Answer:
(d) 1-hexanol

3. The molecular formula C₄H₁₀O represents
(a) aldehydes
(b) alcohols
(c) ethers
(d) both (b) and (c)
Answer:
(d) both (b) and (c)

4. The general formula of primary, secondary and tertiary alcohols is
(a) C_nH_2nOH
(b) C_nH_2n-1OH
(c) C_nH_2n+1OH
(d) C_nH_n+1OH
Answer:
(c) C_nH_2n+1OH

5. Which of the following alcohols cannot be prepared by hydration of the corresponding alkene?
(a) Ethanol
(b) Propan- l-ol
(c) Propan-2-ol
(d) 2-Methylpropan-2-ol
Answer:
(b) Propan- l-ol

6. Which of the following compounds when treated with CH₃MgI in dry ether followed by the hydroly¬sis, will give Propan-2-ol?
(a) HCHO
(b) CH₃CHO
(c) CH₃CH₂OH
(d) CH₃COCH₃
Answer:
(b) CH₃CHO

7. To prepare 3-Ethylpentan-3-ol, the reagents needed are
(a) CH₃CH₂MgBr + CH₃COCH₂CH₃
(b) CH₃MgBr + CH₃CH₂CH₂COCH₂CH₃
(c) CH₃CH₂MgBr + CH₃CH₂COCH₂CH₃
(d) CH₃CH₂CH₂MgBr + CH₃COCH₂CH₃
Answer:
(c) CH₃CH₂MgBr + CH₃CH₂COCH₂CH₃

8. How is 1-propanol obtained?
(a) Using propanal
(b) Using propanone
(c) Using propene
(d) All of these
Answer:
(a) Using propanal

9.

Answer:
(a)

10. Ketone on reduction gives
(a) 1° alcohol
(b) 2° alcohol
(c) 3° alcohol
(d) all of these
Answer:
(b) 2° alcohol

11. Primary alcohols are prepared by catalytic hydro-genation of aldehydes in presence of ……………………………… as a catalyst
(a) aluminium bromide
(b) fluoroboric acid
(c) dry ether
(d) palladium
Answer:
(d) palladium

12. Lower member of alcohols are
(a) insoluble in water
(b) soluble in water
(c) insoluble in acetaldehyde
(d) insoluble in petrol
Answer:
(b) soluble in water

13. Which of the following compounds contain hydro¬gen bonds?
(a) Ethane
(b) Ethanol
(c) Methoxymethane
(d) Ethylene
Answer:
(b) Ethanol

14. Which of the following is a trihydric alcohol?
(a) n-propyl alcohol
(b) Glycerol
(c) Glycol
(d) Glycine
Answer:
(b) Glycerol

15. Aldehydes are first oxidation products of
(a) primary alcohols
(b) secondary alcohols
(c) tertiary alcohols
(d) carboxylic acids
Answer:
(a) primary alcohols

16. The oxidation product of alcohol depends on
(a) – OH group of an alcohol
(b) number of carbon atoms in alcohol
(c) number of hydrogen atoms attached to hydroxyl bearing carbon
(d) all of these
Answer:
(c) number of hydrogen atoms attached to hydroxyl bearing carbon

17. The order of ease of oxidation is
(a) primary > secondary > tertiary
(b) primary < secondary < tertiary
(c) primary > tertiary > secondary
(d) secondary > tertiary > primary
Answer:
(b) primary < secondary < tertiary

18. Ethyl alcohol \(\frac{\text { conc. } \mathrm{H}_{2} \mathrm{SO}_{4}}{443 \mathrm{~K}} \mathrm{~A} \stackrel{\mathrm{HBr}}{\longrightarrow}\) Ethyl bromide. Identify A.
(a) Ethyl hydrogen sulphate
(b) Ethylene
(c) Isopropyl hydrogen sulphate
(d) Acetic acid
Answer:
(b) Ethylene

19. One mole of PCl₅ reacts with one mole of ethyl alcohol to give
(a) 1 mole Cl₂
(b) 1/2 mole Cl₂
(c) 1 mole HCl
(d) 1/2 mole HCl
Answer:
(c) 1 mole HCl

20. When ethyl alcohol is reacted with sodium metal and the compound so formed is treated with ethyl bromide, the product formed is
(a) an acid
(b) an alkane
(c) an ether
(d) an ester
Answer:
(c) an ether

21. Dehydration occurs at the lowest temperature and concentration for
(a) methyl alcohol
(b) n-propyl alcohol
(c) iso-propyl alcohol
(d) tert-butyl alcohol
Answer:
(d) tert-butyl alcohol

22. One mole of sodium when reacts with one mole of methyl alcohol, gives
(a) one mole of oxygen
(b) one mole of hydrogen
(c) half mole of hydrogen
(d) half mole of oxygen
Answer:
(c) half mole of hydrogen

23. A compound ‘X’(C₃H₈O) on oxidation gives com-pound ‘ Y’(C₃H₆O₂), hence compound ‘X’ must be
(a) a ketone
(b) an aldehyde
(c) a primary alcohol
(d) a secondary alcohol
Answer:
(c) a primary alcohol

24. The toxicity of alcohols
(a) increases with an increase in their molecular weight
(b) decreases with an increase in their molecular weight
(c) increases with a decrease in their molecular weight
(d) does not depend on their molecular weight
Answer:
(a) increases with an increase in their molecular weight

25. The structural formula of 2-phenyl ethanol is

Answer:
(c)

26. Compound that fails to give effervescence with NaHCO₃ is
(a) C₆H₅COO
(b) CH₃COOH
(c) C₆H₅OH
(d) Picric acid
Answer:
(c)

27. Phenol is a bifunctional compound because
(a) it gives reactions of hydroxyl group (-OH) as well as aromatic ring
(b) it is a strong acid
(c) it is insoluble in NaOH
(d) it is readily soluble in water
Answer:
(a) it gives reactions of hydroxyl group (-OH) as well as aromatic ring

28. Phenol gives characteristic colour with
(a) iodine solution
(b) bromine water
(c) ammonium hydroxide
(d) aqueous ferric chloride solution
Answer:
(d) aqueous ferric chloride solution

29. Ethanol and phenol are distinguished from each other by the action of
(a) neutral ferrous chloride
(b) neutral ferric chloride
(c) ferric hydroxide
(d) ferrous hydroxide
Answer:
(b) neutral ferric chloride

30. Which of the following compounds is used to prepare bakelite resin?
(a) Acetaldehyde
(b) Ethanol
(c) Phenol
(d) Methyl amine
Answer:
(d) Methyl amine

31. Increasing order of acid strength among p-methoxy-phenol, p-methyl phenol and p-nitro- phenol is as
(a) p-nitrophenol > p-methoxyphenol > p-methylphenol
(b) p-methylphenol > p-methoxyphenol > p-nitrophenol
(c) p-nitrophenol > p-methylphenol > p-methoxyphenol
(d) p-methoxyphenol > p-methylphenol > p-nitrophenol
Answer:
(d) p-methoxyphenol > p-methylphenol > p-nitrophenol

32. The IUPAC name of the compound is
(a) 3,3-dimethyl-l-hydroxy cyclohexane
(b) l,l-dimethyl-3-cyclohexanol
(c) 3,3-dimethyl-1-cyclohexanol
(d) l,l-dimethyl-3-hydroxy cyclohexane
Answer:
(c) 3,3-dimethyl-1-cyclohexanol

33. Which of the following is the most reactive towards electrophilic attack?

Answer:
(a)

34. In the following reaction, Ethanol \(\stackrel{\mathrm{PBr}_{3}}{\longrightarrow} \mathrm{A}\)\(\stackrel{\text { Alc-KOH }}{\longrightarrow} \text { B } \frac{\text { (i) } \mathrm{H}_{2} \mathrm{SO}_{4} \text {, room temp. }}{\text { (ii) } \mathrm{H}_{2} \mathrm{O}, \text { heat }} \mathrm{C} \text {. }\). The product C is
(a) CH₃ – CH₂ – O – CH₂ – CH₃
(b) CH₃ – CH₂ – OSO₃H
(c) CH₃CH₂OH
(d) CH₂ = CH₂
Answer:
(c) CH₃CH₂OH

35. What is the general formula of ethers?
(a) C_nH_2nO
(b) C_nH_2n+2O
(c) C_nH_2n-1O
(d) C_nH_2n-2O
Answer:
(b) C_nH_2n+2O

36. The linkage is present in
(a) proteins
(b) ketones
(c) ethers
(d) aldehydes
Answer:
(c) ethers

37. Methoxy ethane is the functional isomer of
(a) CH₃CHOHCH₃
(b) CH₃CH₂CH₂OH
(c) CH₃ – O – CH₃
(d) both (a) and (b)
Answer:
(d) both (a) and (b)

38. An oxygen atom in ether is
(a) sp²-hybridized
(b) sp³-hybridized
(c) sp-hybridized
(d) sp²-d-hybridized
Answer:
(b) sp³-hybridized

39. C₅H₁₂O represents
(a) only an alcohol
(b) only an aldehyde
(c) only an ether
(d) an alcohol and an ether
Answer:
(d) an alcohol and an ether

40. Ether molecules are
(a) tetrahedral
(b) angular
(c) pyramidal
(d) diagonal
Answer:
(b) angular

41. Which one of the following compounds is not isomeric with Ethoxypropane?
(a) 1-Methoxypropane
(b) 2-Methoxypropane
(c) 2-Methylpropane-2-ol
(d) 2-Methylbutan-2-ol
Answer:
(d) 2-Methylbutan-2-ol

42. The IUPAC name of C₂H₅ – O – CH₂ – CH(CH₃)₂ is
(a) 1-Ethoxy-1-butane
(b) 2-Ethoxy-2-butane
(c) l-Ethoxy-2-methylpropane
(d) 3-Ethoxy-2-methylpropane
Answer:
(c) l-Ethoxy-2-methylpropane

43. The IUPAC name of CH₃OC₆H₅ is
(a) methoxy phenyl ether
(b) phenoxy methane
(c) methoxy benzene
(d) methyl phenyl ether
Answer:
(c) methoxy benzene

44. In CH₃(CH₂)₃ – O -CH₃, the parent hydrocarbon of large alkyl group is
(a) n-butane
(b) butane
(c) pentane
(d) n-pentane
Answer:
(a) n-butane

45. Which one of the following alkyl halide gives best yield in Williamson’s synthesis?
(a) CH₃ – Br
(b) CH₃ – CH(Br) – CH₃
(c) CH₂ – CH(Br) – CH₃ – CH₃
(d) (CH₃)₃ C – Br
Answer:
(a) CH₃ – Br

46. Which one of the following ethers cannot be pre¬pared by using diazomethane?
(a) Dimethyl ether
(b) Diethyl ether
(c) Ethyl methyl ether
(d) t-Butyl methyl ether
Answer:
(b) Diethyl ether

47. The continuous etherification is carried out at
(a) 473 K
(b) 413 K
(c) 498 K
(d) 403 K
Answer:
(b) 413 K

48. Williamson’s synthesis is used for the preparation of
(a) only unsymmetrical ethers
(b) only symmetrical ethers
(c) both symmetrical and unsymmetrical ethers
(d) only methyl ethers
Answer:
(c) both symmetrical and unsymmetrical ethers

49. Which of the following ethers on hydrolysis gives two different products that are successive members of a homologous series?
(a) Methoxymethane
(b) Ethoxythane
(c) Methoxyethane
(d) 2-Methoxypropane
Answer:
(c) Methoxyethane

50. Which one of the following compounds dissolves in hot dilute sulphuric acid but does not react with sodium metal?
(a) Ethyl bromide
(b) Acetic acid
(c) Ethyl alcohol
(d) Diethyl ether
Answer:
(d) Diethyl ether

51. Identify ‘A’ in the following reaction :

Answer:
(c)

52. The C-O-C bond angle in an ether is
(a) 180
(b) 90°
(c) 104.5°
(d) 109.5°
Answer:
(d) 109.5°

53. Ether free from moisture and alcohol is known as ,
(a) dry ether
(b) absolute ether
(c) pure ether
(d) spirit ether
Answer:
(b) absolute ether

54. The geometry of ether is similar to
(a) ammonia
(b) methane
(c) water
(d) ethyne
Answer:
(c) water

55. Sodium metal does not react with
Answer:
C₂H₅ – O – C₂H₃

56. Ethers have boiling points
(a) lower than those of alkanes of comparable molecular masses
(b) higher than those of isomeric alcohols
(c) lower than those of isomeric alcohols
(d) higher than those of alkanes of comparable molecular masses
Answer:

57. Ether on hydrolysis gives
(a) aldehyde
(b) alcohol
(c) acid
(d) ester
Answer:
(c) acid

58. Which of the following reactions represent Williamson’s reaction?
(a) R – O – R’ + HI →
\(\text { (b) } \mathrm{R}^{\prime}-\mathrm{OH}+\stackrel{\mathrm{H}_{2} \mathrm{SO}_{4}}{\longrightarrow}\)

(d) R – O – Na + R’X →
Answer:
(c)

59. Which of the following reactions represent the continuous etherification process?

Answer:
(b)

60. Ethers on complete combustion produce
(a) an alcohol and water
(b) an alkene and water
(c) an alkane and an alkene
(d) carbon dioxide and water
Answer:
(d) carbon dioxide and water

61. Diethyl ether is used as a solvent in many organic reactions because it
(a) is liquid at room temperature
(b) has lower boiling point
(c) contains divalent oxygen atom
(d) is inert in nature
Answer:
(d) is inert in nature

62. Which of the following reagents can be prepared using ether as a solvent?
(a) Tollen’s reagent
(b) Grignard’s reagent
(c) Schiff’s reagent
(d) Millon’s reagent
Answer:
(b) Grignard’s reagent

63. Diethyl ether is used as
(a) a hypnotic
(b) an antiseptic
(c) an anaesthetic
(d) an antipyretic
Answer:
(c) an anaesthetic

64. To obtain fuel, diethyl ether is mixed with
(a) ester
(b) ethanal
(c) ethanol
(d) 2-propanone
Answer:
(c) ethanol

65. Which of the following alcohols is prepared by acid catalyzed hydration of alkenes?
(a) Butan-l-ol
(b) Propan-l-ol
(c) Ethanol
(d) Methanol
Answer:
(c) Ethanol

66. Which of the following alcohols can be prepared by direct hydration of corresponding alkene in presence of 50 % sulphuric acid?
(a) Butan-l-ol
(b) Butan-2-ol
(c) 2-Methylpropan-1 -ol
(d) 2-Methylpropan-2-ol
Answer:
(d) 2-Methylpropan-2-ol

67. Which of the following alcohols cannot be prepared by reduction of carbonyl compounds?
(a) Pentan-l-ol
(b) Pentan-2-ol
(c) 2-Methylpentan-2-ol
(d) 3-Methylpentan-2-ol
Answer:
(c) 2-Methylpentan-2-ol

68. Which of the following conversions explains the acidic nature of alcohols?

Answer:
(b)

69. Which of the following compounds gives 3-ethyl- pentan-3-ol by the action of ethyl magnesium iodide followed by acid hydrolysis?
(a) Propanone
(b) Butanone
(c) Pentan-2-one
(d) Pentan-3-one
Answer:
(d) Pentan-3-one

70. Benzyl phenyl ether reacts with hydrogen bromide to give
(a) benzyl bromide and phenol
(b) benzyl alcohol and bromobenzene
(c) benzyl bromide and bromobenzene
(d) benzyl alcohol and phenol
Answer:
(a) benzyl bromide and phenol

71. Ethers are considered as
(a) monoalkyl derivatives of water
(b) divalent oxygen atom is attached to two alkyl groups
(c) alkyl derivatives of fatty acids
(d) condensation products of acid and alcohol
Answer:
(b) divalent oxygen atom is attached to two alkyl groups

72. Which of the following compounds is not isomeric with ethoxyethane?
(a) 1-methoxypropane
(b) 2-methoxypropane
(c) 2-methylpropan-2-ol
(d) 2-methylbutan-2-ol
Answer:
(d) 2-methylbutan-2-ol

73. Which of the following compounds dissolves in hot dilute sulphuric acid but does not reacts with sodium metal?
(a) Ethyl bromide
(b) Acetic acid
(c) Ethyl alcohol
(d) Diethyl ether
Answer:
(d) Diethyl ether

74. Which of the following alcohol will have the fastest rate of dehydration?

Answer:
(c)

75. The phenol having lowest acidity is

Answer:
(b)

76. Which of the following reagents is best for the following conversion?

Answer:
(a)

77. 3-Methyl butane-2-ol on heating with HI gives
(a) 2 -iodo-3-methyl butane
(b) 2-iodo-2-methyl butane
(c) l-iodo-3-methyl butane
(d) l-iodo-2-methyl butane
Answer:
(b) 2-iodo-2-methyl butane

78. In phenol carbon atom attached to -OH group undergoes –
(a) sp³-hybridisation
(b) sp-hybridisation
(c) sp²-hybridisation
(d) No hybridisation
Answer:
(c) sp²-hybridisation

79. Which among the following reducing agents is ‘not’ used to reduce acetaldehyde to ethyl alcohol?
(a) Na-Hg and water
(b) Zn-Hg and cone. HCl
(c) H₂-Raney Ni
(d) Li-A1H₄/H⁺
Answer:
(b) Zn-Hg and cone. HCl

80. Identify the weakest acidic compound amongst the following :
(a) p-nitrophenol
(b) p-chlorophenol
(c) p-cresol
(d) p-aminophenol
Answer:
(d) p-aminophenol

81. Natalite is a mixture of
(a) diethyl ether and methanol
(b) diethyl ether and ethanol
(c) dimethyl ether and methanol
(d) dimethyl ether and ethanol
Answer:
(b) diethyl ether and ethanol

82. The alcohol used in thermometers is
(a) methanol
(b) ethanol
(c) propanol
(d) butanol
Answer:
(b) ethanol

83. Which of the following is the first oxidation product of secondary alcohol?
(a) Alkene
(b) Aldehyde
(c) Ketone
(d) Carboxylic acid
Answer:
(c) Ketone

84. When phenol is heated with cone. HNO₃ in presence of cone. H₂SO₄ it yields
(a) o-nitrophenol
(b) p-nitrophenol
(c) 2, 4, 6-trinitrophenol
(d) m-nitrophenol
Answer:
(c) 2, 4, 6-trinitrophenol

Balbharti Maharashtra State Board 12th Chemistry Important Questions Chapter 1 Solid State Important Questions and Answers.

Maharashtra State Board 12th Chemistry Important Questions Chapter 1 Solid State

Question 1.
What are the physical states of matter? How can they be changed into one another?
Answer:

• There are three physical states of matter namely solid, liquid and gas.
• They differ in intermolecular or interatomic or interionic forces which are strongest in the solid-state.
• By raising the temperature of solids to their melting point, solids are converted into liquids while heating liquids to their boiling points, they can be converted into vapour or gaseous state.
• On the contrary, by cooling the gases to very low temperature and subjecting to high pressure they can be transformed into liquid which on further cooling can be transformed into solid-state.

The equilibrium existing between three states of matter may be represented as,

Question 2.
What are the constituents of solids?
Answer:
The smallest constituent particles of various solids are atoms, ions or molecules. All such small constituents are referred to as ‘particles’.

Question 3.
What are the characteristic properties of solids?
Answer:

• The solid state of matter is characterised by strong interparticle forces of attraction.
• There is regularity and periodicity in the arrangement of constituent particles of solid.
• Generally solids are hard, incompressible and rigid except some solids like Na, K, P which are soft.
• The constituent particles of solids like molecules, atoms or ions have fixed stationary positions in solid and can only oscillate about their equilibrium or mean positions. Hence, they have fixed shape and cannot be poured like liquids.
• Crystalline solids have sharp melting points and they melt at a definite temperature. Amorphous solids do not have sharp melting points.
• They are anisotropic or isotropic.

Question 4.
Give classification of solids.
Answer:
Depending on orderly arrangement of the constituent particles, the solids are classified into two types :

• Crystalline solids. For example, diamond, NaCl, K₂SO₄, etc.
• Amorphous solids or non-crystalline solids. For example, tar, glass, plastics, rubber, butter, etc.

Question 5.
Define :
(1) Crystalline solid.
(2) Amorphous solid.
Answer:
(1) Crystalline solid : A homogeneous solid in which the constituent particles like atoms, ions or molecules are arranged in a definite repeating pattern throughout the solid is called crystalline solid. For example, NaCl, KNO₃, etc.

(2) Amorphous solid : A substance which appears like solid but does not have perfectly ordered crystalline structure and no regular arrangement of constituent particles in structure is called amorphous solid. For example, glass, rubber, plastics, etc.

Question 6.
Define the term anisotropy.
OR
Define and explain the term anisotropy.
Answer:
Anisotropy : The ability of crystalline solids to change their physical properties when measured in different directions is called anisotropy.

Explanation : This property is due to different arrangement of constituents in different directions. Different types of particles fall on the way of measurements in different directions. Hence the composition of crystalline solid changes with directions changing their physical properties.

Fig. 1.1 : Anisotropy in crystals : Different arrangements of constituent particles about different directions, AB, CD and EF.

Question 7.
Define and explain isotropy.
Answer:
Isotropy : The ability of amorphous solids to exhibit identical physical properties even though measured in different directions is called isotropy.

Explanation : This property arises because there is no long range order of regular pattern of arrangement in them and hence the arrangement is irregular along all the directions. Therefore the magnitude of any physical property would be identical along all directions.

Question 8.
Why does crystalline solid show different refractive indices in different directions ?
Answer:

1. Crystalline solid has long range order of regular pattern of arrangement which repeats periodically over entire crystal.
2. Within the given pattern, the arrangements of different atoms or ions or molecules is different in different directions. Hence the properties like refractive indices in the different directions are different.

This shows that the crystalline solids are anisotropic in nature.

Question 9.
Explain the properties of amorphous solids.
Answer:

1. The constituent particles in amorphous solids are arranged randomly.
2. They have short range ordered structure.
3. Amorphous solids are called supercooled liquids having very high viscosity.
4. They do not have sharp melting points and they melt gradually over a temperature interval.
5. Amorphous substances appear like solids but they do not have perfectly ordered crystalline structure, hence they are not real solids. Therefore they are pseudo solids.
6. They are isotropic and exhibit the same magnitude of any property in every direction.

Question 10.
What is isomorphism ?
Answer:
Isomorphism : A phenomenon in which two or more crystalline substances show same crystalline structure is called isomorphism and the crystals are said to be isomorphous. For example, NaNO₃ and CaCO₃. They have atomic ratios 1 : 1 : 3.

Question 11.
What is isomorphous?
Answer:
Isomorphous : When two or more crystalline substances have the same crystalline structure, they are said to be isomorphous. For example, NaF and MgO, NaNO₃ and CaCO₃.

Question 12.
What is polymorphism ?
Answer:
Polymorphism : A phenomenon in which when a single substance crystallises in two or more forms under different conditions of solidification is called polymorphism and the substance is called polymorphous. For example, calcite and oragonite are two forms of CaCO₃.

Question 13.
What is polymorphous ?
Answer:
Polymorphous: A single substance which crystallises in two or more forms under different conditions of solidification is called polymorphous. Polymorphic forms of an element are called allotropic forms or allotropes. For example, carbon exists as diamond and graphite, or sulphur exists in rhombic and monoclinic allotropic forms.

Question 14.
Identify isomorphous and polymorphous substances in the following :
K₂SO₄, graphite, β-quartz, Na₂SeO₄, CaCO₃, diamond, cristobalite, C_sNO₃.
Answer:

Isomorphous	Polymorphous
K2SO4, Na2SeO4 CaCO3, CsNO3	Graphite, diamond Β-quartz, cristobalite

Question 15.
Why does a crystalline solid has a sharp melting point ?
Answer:

1. Crystalline solid is a homogeneous solid and it has long range order of regular pattern of arrangement which repeats periodically over entire crystal.
2. The interatomic or intermolecular forces are identical, hence the thermal energy required to break the regular structure by overcoming the intermolecular forces is uniform throughout.
3. Hence the heat and temperature needed to melt the solid are same, and therefore solids have sharp melting points.

Question 16.
Amorphous solids do not have sharp melting points. Explain.
Answer:

1. Amorphous solids do not have perfectly ordered crystalline structure.
2. They have short range order of regular pattern hence periodically repeating regular pattern is over a short distance.
3. The thermal energy required to break the structure and separate constituent particles is not uniform.
4. Hence the temperature needed to melt the solid is not same, therefore amorphous solids do not have sharp melting points but melt over a range of temperature.

Question 17.
Give examples of (1) crystalline solids and (2) amorphous solids.
Answer:
(1) Crystalline solids : Metallic solids (Cu, Fe, etc.) crystalline salts (NaCl, K₂SO₄, etc.)
(2) Amorphous solids : Glass, plastics, rubber, etc.

Question 18.
Distinguish between crystalline solids and amorphous solids.
Answer:
Crystalline solids:

1. They have definite characteristic geometrical shape.
2. They have long range order of regular pattern of arrangement of constituent particles.
3. They are true solids.
4. They have sharp melting points.
5. They are anisotropic in nature.
6. They have definite heat of fusion.

Amorphous solids:

1. They have irregular shape.
2. They have short range order of regular pattern of arrangement of constituent particles.
3. They are pseudo solids or supercooled liquids.
4. They do not have sharp melting points.
5. They are isotropic in nature.
6. They do not have definite heat of fusion.

Question 19.
How are crystalline solids classified ?
Answer:
Crystalline solids are classified as follows :

1. Ionic crystals
2. Covalent network crystals
3. Molecular crystals
4. Metallic crystals

Question 20.
What are crystalline solids?
Answer:
The solids in which the constituent particles are charged ions namely cations and anions held together by electrostatic force of attraction are called crystalline solids.

Question 21.
What are the characteristics of ionic crystals ?
Answer:
The characteristics of ionic crystals are as follows :

1. The constituents of ionic crystals are charged ions namely cations and anions. They differ in ionic size.
2. The ions in these crystals are held by strong electrostatic force of attraction.
3. Ionic crystals have high melting points and they are hard and brittle.
4. In solid state they are nonconductors of electricity but they are good conductors when melted or dissolved in water.
5. In aqueous solution they dissociate forming ions.
6. Example : NaCl, KCl. CaF₂, K₂SO₄, etc.

Question 22.
Explain why ionic solids are hard and brittle.
Answer:

1. In ionic crystalline solids, constituent particles are positively charged cations and negatively charged anions placed at alternate lattice points.
2. The ions are held by strong coulombic electrostatic forces of attraction compensating opposite forces. Hence they are hard.
3. Since there are no free electrons, they are not malleable and on applying a shearing force, ionic crystals break into small units. Hence they are brittle.

Question 23.
What are covalent network crystals ?
Answer:
The crystals in which the constituent particles are atoms linked by covalent bonds forming a continuous network are called covalent network crystals. For example, diamond, quartz.

Question 24.
What are the characteristics of covalent network crystals ?
Answer:
The characteristics of covalent network crystals are as follows :

• The constituent particles in these solids are atoms.
• The atoms in these crystals are held by covalent bonds forming a rigid three dimensional network which gives a giant molecule. Hence, the entire crystal is a single molecule.
• These crystals are very hard (or hardest) and most incompressible.
• They have high melting points and boiling points.
• Since the electrons are localised they are poor conductors of heat and electricity.
• Example : Quartz (SiO₂), diamond.

Question 25.
Give the examples of network solids.
Answer:
The examples of covalent network solids are as follows :
Quartz (SiO₂), diamond, boron nitride carborundum.

Question 26.
What are allotropes ?
Answer:
Allotropes : When a substance exists in two or more forms then they are called allotropes. They are polymorphous. For example, carbon has allotropes diamond and graphite.

Question 27.
What are molecular crystals ?
Answer:
The crystals in which the constituent particles are molecules (or unbonded single atoms) of the same substance held together by intermolecular forces of attraction. For example solidified Cl₂, CO₂, etc.

Question 28.
What are the characteristics of molecular crystals ?
Answer:
The characteristics of molecular crystals are as follows :

1. The constituent particles of these solids are molecules (or unbonded single atoms) of the same substance.
2. The atoms within the molecules are bonded by covalent bonds.
3. The molecules are held together by intermolecular forces of attraction.

Question 29.
What are intermolecular forces of attraction involved in molecular crystals ?
Answer:
The intermolecular forces involved in molecular crystals are as follows :
(1) Weak dipole-dipole interactions :
The solids constituting polar molecules like HCl, H₂O, SO₂, etc. which possess permanent dipole moment involve weak dipole-dipole interactions.

(2) Very weak dispersion or London forces :
The solids consisting of nonpolar molecules like CH₄, H₂, etc. involve weak dispersion forces. They are also involved in monoatomic solids like Ar, Ne.

(3) Intermolecular Hydrogen bonds :

• In this crystalline solids, the constituent particles are the molecules which contain hydrogen atom linked to highly electronegative atom like F, O or N.
• In these, molecules are held by hydrogen bonds in which H atom of one molecule is bonded to electronegative atom (like F, N or O) of another molecule.
• Since hydrogen bonding is weak, these solids have very low melting points and generally at room temperature they exist in the liquid or gaseous state.
• They are non-conductors of electricity.

Question 30.
What are metallic crystals ?
Answer:
These are crystalline solids formed by atoms of the same metallic element held together by metallic bonds.

Question 31.
What are the characteristics of metallic crystals ?
Answer:

1. Metallic crystals are solids formed by atoms of the same metallic element held together by metallic bonds.
2. Metallic crystals have high melting point and boiling point.
3. Metals are malleable and can be hammered into thin sheets.
4. Metals are ductile and can be drawn into thin wires.
5. Metals are good conductors of heat and electricity.
6. Examples are Cu, Ag, Au, Ni, etc.

Question 32.
Classify the following solids into different types :
(i) Plastic (ii) P₄ molecule (iii) S₈ molecule (iv) Iodine molecule (v) Tetra phosphorus decoxide (vi) Ammonium phosphate (vii) Brass (viii) Rubidium (ix) Graphite (x) Diamond (xi) NaCl (xii) Silicon.
Answer:

Solid	Type
(i) Plastic	Covalent network crystal
(ii) P4 molecule	Covalent network crystal
(iii) S8 molecule	Covalent network crystal
(iv) Iodine molecule	Covalent network crystal
(v) Tetra phosphorus decoxide	Covalent network crystal
(vi) Ammonium phosphate	Ionic crystal
(vii) Brass	Metalic crystal
(viii) Rubidium	Metalic crystal
(ix) Graphite	Covalent crystal
(x) Diamond	Covalent crystal
(xi) NaCl	Ionic crystal
(xii) Silicon	Covalent crystal

Question 33.
Mention the types of the following solids :
(i) CaF₂ (ii) SiC (iii) Ice (iv) SO₂ (v) CaCO₃ (vi) ZnS (vii) HCl (viii) CO₂
Answer:

Solid	Type
(i) CaF2	Ionic crystal
(ii) SiC	Covalent crystal
(iii) Ice	Hydrogen bonded molecular crystal
(iv) SO2	Molecular crystal
(v) CaCO3	Ionic crystal
(vi) ZnS	Ionic crystal
(vii) HCl	Polar molecular crystal
(viii) CO2	Non-polar molecular crystal

Question 34.
What is a giant solid ?
Answer:
Covalent solid formed by covalent bonds between neighbouring constituent atoms of non-metallic solid is called a giant solid. For example, graphite.

Question 35.
What is lattice ?
Answer:
Lattice is a geometrical arrangement of points in a three dimensional periodic array.

Question 36.
What is crystal lattice (space lattice) ?
Answer:
Crystal lattice (space lattice) : A regular arrangement of the constituent particles (atoms, ions or molecules) of a crystalline solid having similar environment in three dimensional space is called crystal lattice or space lattice.

Question 37.
What is a lattice point?
Answer:
Lattice point : A position occupied by a crystal constituent particle like an atom, ion or a molecule in the crystal lattice is called lattice point or lattice site.
OR
Any point at the intersection of the lines in the unit cell occupied by a constituent particle like an atom, an ion or a molecule in the crystalline solid is called a lattice point.

Question 38.
What are the parameters of a unit cell ?
Answer:
A unit cell is characterised by following parameters :
(1) Edges or edge lengths : The intersection of two faces of crystal lattice is called as edge. The three edges denoted by a, b and c represent the dimensions (lengths) of the unit cell along three axes. These edges may or may not be mutually perpendicular.

(2) Angles between the edges (or planes) : There are three angles between the edges of the unit cell represented as α, β and γ.

• The angle α is between edges b and c.
• The angle β is between edges a and c.
• The angle γ is between edges a and b.

The crystal is defined with the help of these parameters of its unit cell.

Question 39.
Represent space lattice and unit cell diagrammatically.
Answer:

Question 40.
What do you understand by the basis of crystal lattice ?
Answer:

• A crystal structure is formed by attaching a constituent particle to lattice points.
• The constituent particles attached to the lattice points form the basis of the crystal lattice.
• The crystal structure is obtained by attaching a basis to each of the lattice points.

This is represented by the following schematic equation :

Question 41.
What are the types of unit cells?
Answer:
Basically unit cells are of two types as follows :

1. Primitive unit cells : The unit cells in which the constituent particles like atoms, ions or molecules are present only at the corners of the unit cell are called primitive unit cells or simple unit cells.
2. Body-centred unit cell : A unit cell in which the constituent particles are present at the corners as well as at its body-centre is called body-centred unit cell.
3. Face-centred unit cell : A unit cell in which the constituent particles are present at the corners as well as at the centre of each face is called face-centred unit cell or cubic close packed (CCP) unit cell.
4. Base-centred unit cell : A unit cell in which the constituent particles are present at the corners as well as at the centres of two opposite faces is called end-centred unit cell.

Question 42.
Explain briefly crystal systems.
Answer:
(1) The constituent particles like atoms, ions or molecules of the crystal can be arranged in seven different ways changing edges (a, b, c) and angles (α, β, γ) and accordingly they form seven systems or types of the crystal.

(2) These seven crystal system are named as :
(a) Cubic system, (b) Tetragonal system (c) Orthorhombic system (d) Rhombohedral system (e) Monoclinic system (f) Triclinic system (g) Hexagonal system.

Question 43.
What are Bravais lattices ?
Answer:

1. There are seven crystal systems according to the edges (a. b, c) and angles (α, β, γ).
2. The constituents of the crystal may be present at corners, face centres, body centres, edge centres and voids.
3. By mathematical analysis, it has been proved that only fourteen different kinds of space lattices are possible.
4. Hence there are fourteen different ways of arrangement of the lattice basis.
5. These fourteen lattices of seven crystal systems are called Bravais lattices.

Question 44.
Explain Bravais lattices of a cubic system.
OR
Explain unit cells of a cubic system.
Answer:
Cubic lattice : For this, edges are a = b = c and angles are α = β = γ = 90°. In this cubic system, there are three Bravais lattices.
(1) Simple (or primitive) cubic unit cell (SCC) : In this unit cell, atoms are present only at 8 corners of the cube.

(2) Body-centred cubic unit cell (BCC) : In this, atoms are present at 8 corners along with one additional atom at the body-centre of the cube.

(3) Face-centred cubic unit cell (FCC) : In this unit cell, atoms are present at 8 comers and at 6 face centres.

Question 45.
Give the number of lattice points in one unit cell of the following crystal structures :
(1) Simple cubic
(2) Face-centred cubic
(3) Body-centred cubic.
Answer:
Lattice points in one unit cell represent the positions of atoms, ions or molecules in the unit cell.
(1) Simple cubic unit cell : In this primitive unit cell, the lattice points are at 8 corners of the unit cell. Hence there are 8 lattice points.
(2) Face-centred cubic unit cell : In this unit cell, the lattice points are at 8 comers and 6 face centres.
(In cubic close packing unit cell, the lattice points are also at edge centres and body centre.)
(3) Body-centred cubic unit cell : In this, the lattice points are at 8 comers and one at body centre.

Question 46.
Find the number of atoms per unit cell in the following crystal structures.
(1) Simple cubic unit cell
(2) Body-centred cubic unit cell
(3) Face-centred cubic cell.
Answer:
(1) Number of atoms in primitive simple cubic (scc) unit cell :

In simple or primitive cubic unit cell, there are 8 atoms at 8 corners. Each corner contributes 1/8th atom to the unit cell.
∴ Number of atoms present in the unit cell = \(\frac {1}{8}\) × 8 = 1
Hence the volume of the unit cell is equal to the volume of one atom.

(2) Number of atoms in body-centred cubic (bcc) unit cell:

In this unit cell, there are 8 atoms at 8 corners and one additional atom at the body centre. Each corner contributes 1/8th atom, to the unit cell, hence due to 8 corners.
Number of atoms = 8 × \(\frac {1}{8}\)
= 1 atom.
An atom at the body centre wholly belongs to the unit cell.
∴ Total number of atoms present in bcc unit cell = 1 + 1 = 2.
Hence the volume of unit cell is equal to the volume of two atoms.

(3) Number of atoms in face-centred cubic (fcc) unit cell :

In this unit cell, there are 8 atoms at 8 comers and 6 atoms at 6 face centres. Each corner contributes 1/8th atom to the unit cell, hence due to 8 corners,
Number of atoms = \(\frac {1}{8}\) × 8 = 1.
Each face centre contributes half of the atom to the unit cell, hence due to 6 face centres,
Number of atoms = \(\frac {1}{2}\) × 6 = 3.
∴ Total number of atoms present in fee unit cell = 1 + 3 = 4.
Hence the volume of the unit cell is equal to the volume of four atoms.

Question 47.
Obtain a relation for the density of the unit cell and radius of atom or sphere for the following :
(1) Simple cubic (scc) crystal
(2) Body centred cubic (bcc) crystal
(3) Face centred cubic (fcc) crystal.
Answer:
(1) Consider a unit cell of a simple cubic crystal. It has 8 atoms at 8 corners of the unit cell.
∴ Total number of atoms in unit cell = \(\frac {1}{8}\) × 8 = 1
If a is the length of edge of cubic unit cell and r is the radius of the atom, then r = a/2 or a = 2r.
Volume of the unit cell = a³ = (2r)³ = 8r³
If M is atomic mass of the element, then mass of one atom is M/N_A where N_A is Avogadro number. If there are V atoms in one unit cell then,
Mass of unit cell = n × Mass of one atom = n × \(\frac{M}{N_{\mathrm{A}}}\)

Since there is one atom present in one unit cell,
ρ = \(\frac{M}{N_{\mathrm{A}} \times a^{3}}\)

(2) Consider a unit cell of body centred cubic (bcc) crystal. It has 8 atoms at 8 comers and one additional atom at the centre of body of unit cell.
Number of atoms due to 8 corners = \(\frac {1}{8}\) × 8 = 1
Body centred atom, wholly belong to the unit cell. Hence total number of atoms in the unit cell is two. If M is atomic mass of an element then M/N_A is mass of one atom where N_A is Avogadro number.
Mass of unit cell = Mass of 2 atoms in unit cell = 2 M/N_A
If a is the edge length or lattice parameter then,
Volume of cubic unit cell = a³

(3) Consider a unit cell of face centred cubic (fcc) crystal.
It has 8 atoms at 8 comers and 6 atoms at 6 face centres.
∴ Total number of atoms in unit cell = \(\frac {1}{8}\) × 8 + \(\frac {1}{2}\) × 6 = 1 + 3= 4
If M is the atomic mass of an element, then mass of one atom is M/N_A, where N_A is Avogadro number. Mass of unit cell = Mass of 4 atoms
= \(4 \times \frac{M}{N_{\mathrm{A}}}\)
If a is the edge length of this cubic unit cell then,
volume of unit cell = a³

Question 48.
What is coordination number? What is its significance?
Answer:
(1) Coordination number : The number of the closest neighbouring constituent particles like atoms, ions or molecules which are in contact with a particular particle or an atom in the crystal lattice is called coordination number of that particle.
(In the crystal lattice, all atoms may have same or different coordination numbers.)

(2) The magnitude of the coordination number is a measure of compactness of spheres in close-packed structures.

(3) The higher the coordination number, the closer are the spheres to each other.

Question 49.
Explain linear packing in one direction.
OR
Explain close packing in one dimension.
Answer:
Linear packing in one direction or close packing in one dimension :
The constituent particles of the crystal may be of varying shapes but for better understanding we consider particles as hard spheres of equal size.

There is only one way of arranging or packing spheres placed in a horizontal row touching one another. Since one sphere is in contact with two neighbouring spheres except the end atoms, the coordination number in this arrangement is two. This packing may be in any one direction x, y or z.

Question 50.
Explain the following :
Planar packing arrangement of spheres.
OR
Close packing in two dimensions.
OR
AAAA type and ABAB type of two dimensional arrangement.
OR
(i) Square close packing
(ii) Hexagonal close packing.
Answer:
Two dimensional close packing crystal structure can be generated by placing one dimensional linear crystal structure over another to form multiple layers. This staking of linear rows may be taking place in two different ways giving two different two dimensional structures as follows :

(i) AAAA type two dimensional close packing or square close packing :
In this arrangement, various one dimensional rows are placed on one over other so that each sphere in one row is over the another sphere of another row forming planar structure. In this, spheres have horizontal as well as vertical alignment. All the rows of spheres are identical in planar structure. All crests as well as all the depressions or troughs formed by the arrangement are also aligned.

If the first row is labelled as A type, then second and all subsequent rows are also identical, hence are of A type. Therefore this planar two dimensional close packing is called AAAA type packing.

In this arrangement, each sphere is in contact with (or touching) four other spheres around it, hence the coordination number of each sphere is four and the packing is called two dimensional or planar square close packing. In this, packing efficiency is 52.4%.

(ii) ABAB type two dimensional packing or hexag-onal close packing :

In this arrangement, crests of the spheres of one row are placed into the depressions or troughs formed between adjacent spheres of next row. This arrangement is repeated consecutively throughout.

In this arrangement, crests of the spheres of one row are in contact with depressions or troughs of next row.

If one row of spheres is labelled as A then the next row will be B, third row will again be A, fourth row B and so on. Hence this planar or two dimensional close packing is called ABAB… type packing.

In this arrangement, each sphere is in contact with six other spheres around it hence the coordination number of each sphere is six and the packing is called two dimensional or planar hexagonal close packing. In this, the packing efficiency is 60.4% which is more than linear close packing.

Question 51.
Explain close packing in three dimensions.
Answer:
Close packing in three dimensions :
Three dimensional crystal structures are obtained by stacking of two dimensional layers. Simple cubic lattice is obtained by stacking of two dimensional square layers.

The stacking of two dimensional hexagonal close packed layers gives two structures namely hexagonal close packed (hcp) structure and face centred (fcc) structure.

(i) Stacking of square close packed layers :

In this arrangement, the two dimensional AAAA type square closed packed layers are placed one over the other in such a way that the crests of all spheres are in contact with successive layers in all directions. All spheres of different layers are perfectly aligned horizontally and vertically forming unit cells having primitive or simple cubic structure. Since all the layers are identical and if each layer is labelled as layer A, then whole three dimensional crystal lattice will be of AAAA… type.

Each sphere is in contact with six surrounded spheres, hence the co-ordination number of each sphere is six.

(ii) Stacking of two hexagonal close packed layers :
A close packed three dimensional structure can be generated by arranging hexagonal close packed layers in a particular manner.

In this the spheres of second layer are placed in the depression of the first layer.

In this if first layer is labelled as A then second layer is labelled as B since they are aligned differently.

In this, all triangular voids of the first layers are not covered by the spheres of the second layer. The triangular voids which are covered by second layer spheres generate tetrahedral void which is surrounded by four spheres. The triangular voids in one layer have above them triangular voids of successive layers.

The overlapping triangular voids from two layers together form an octahedral void which is surrounded by six spheres.

(iii) Placing third hexagonal close packed layer :
(a) Hexagonal close packing (hcp) : If the crests of spheres of third layer are placed on the triangular shaped tetrahedral voids C of the second layer, then three dimensional closest packing structure is obtained in which the spheres of third layer lie directly above the spheres of first layer, i.e., first and third layers are identical. Following same placing of layers, fourth layer will be identical to second layer.

If the first layer is labelled A and second layer B, then the arrangement of packing will be of ABAB type. This is also called hexagonal close packing (hcp) as shown in the figure. In this, packing efficiency is 74%. The coordination number of each sphere is 12. The metals Be. Mg, Zn, Cd crystallise in HCP crystalline structure.

(b) Cubic close packing (ccp) : If the crests of spheres of third layer are placed in the positions of tetrahedral void ‘a’ having apex upward of first layers, then the third layer will not be identical to the first, and may be labelled as C, which is different from A and B layers. Fourth layer may be arranged above third layer such that the spheres are aligned, so that the first layer and fourth layer are identical, second and fifth layers are identical and so on.

If first, second and third layers are labelled as A, B and C respectively then the arrangement of packing will be ABCABC type. This is also called cubic close packing (ccp) as shown in the figure. This is similar to face centred cubic (fcc) packing.

In this, arrangement packing efficiency is 74% and the coordination number of each sphere is 12.

Question 52.
Explain tetrahedral void.
Answer:
(1) Tetrahedral void : The vacant space or void among four constituent particles having tetrahedral arrangement in the crystal lattice is called tetrahedral void.

The arrangement of four spheres around the void is tetrahedral. A tetrahedral void is formed when a triangular void made by three coplanar spheres is in contact with fourth sphere above or below it.

(2) Characteristics of tetrahedral void :

• The volume of the void is much smaller than that of atom or sphere.
• Larger the size of sphere, more is the size of void.
• If R is the radius of the constituent atom, then the radius of the tetrahedral void is 0.225 R.
• Coordination number of tetrahedral void is four.
• There are two tetrahedral voids per sphere, in the crystal lattice. If the number of closed packed spheres is N then the number of tetrahedral voids is 2N.

Question 53.
Explain octahedral void.
Answer:
(1) Octahedral void : The vacant space or void at the centre of six spheres (or atoms) which are placed octahedrally is called octahedral void.

(2) Characteristics of octahedral void :

• The volume of the void is small.
• There is one octahedral void at the body centre and twelve octahedral void positions at twelve edge centres.
• If R is the radius of constituent atom, then the radius of the octahedral void is 0.414 R.
• The coordination number of octahedral void is six.
• There is one octahedral void per sphere in the crystal lattice. If the number of closed packed spheres is N then the number of octahedral voids is N.

Question 54.
What are number of voids per atom in hep and ccp ?
Answer:
The tetrahedral and octahedral voids occur in hep and ccp/fcc structures. There are two tetrahedral voids associated with each atom. The number of octahedral voids is half that of tetrahedral voids. Thus, there is one octahedral void per atom.

Question 55.
What is packing efficiency?
Answer:
(1) Packing efficiency : It is the fraction of a percentage of the total space (of the unit cell) occupied by the particles (spheres).

( 2) The magnitude of packing efficiency gives a measure of how tightly particles are packed together.

Question 56.
Calculate packing efficiency in body-centred cubic lattice.
Answer:
Step 1 : Radius of sphere :
In the unit cell of body-centred cubic lattice, there are 8 atoms at 8 corners and one atom at the centre of the cube.

The atoms are in contact along the body diagonal BF. Let a be the edge length and r the radius of an atom.
Consider a triangle BCE.
BE² = BC² + CE² = a² + a² = 2a²
Consider triangle BEF,
BF² = BE² + EF² = 2a² + a² = 3a²
BF = \(\sqrt{3}\)a.
From figure, BF = 4r
∴ 4r = \(\sqrt{3}\)a
∴ r = \(\frac{\sqrt{3}}{4} a\)

Step 2 : Volume of sphere :

Step 3 : Total volume of particles :
The unit cell of bcc structure contains 2 particles.

Step 4 : Packing efficiency

∴ Packing efficiency = 68%
∴ Percentage of void space = 100 – 68
= 32%

Question 57.
Calculate packing efficiency in face-centred cubic lattice.
Answer:
Step 1 : Radius of sphere :
In the unit cell of face-centred cubic lattice, there 8 atoms at 8 corners and 6 atoms at 6 face centres. Consider the face ABCD.

The atoms are in contact along the face diagonal BD.
Let a be the edge length and r, the radius of an atom.
Consider a triangle BCD.
BD² = BC² + CD²
= a² + a² = 2a
∴ BD = \(\sqrt{2} a\)
From figure, BD = 4r

Step 3 : Total volume of particles :
The unit cell of fee crystal lattice contains 4 particles.
∴ Volume occupied by 4 particles = \(4 \times \frac{\pi a^{3}}{12 \sqrt{2}}\)
= \(\frac{\pi a^{3}}{3 \sqrt{2}}\)

Step 4 : Packing efficiency :

∴ Packing efficiency = 74%
∴ Percentage of void space = 100 – 74
= 26%

Edge length and particle parameters in cubic system

Coordination number and packing efficiency in systems

Lattice	Coordination number of atoms	Packing efficiency
1. scc	6 : four in the same layer, one directly above and one directly below	52.4%
2. bcc	8 : four in the layer below and four in the layer above	68%
3. fcc/ccp/hcp	12 : six in its own layer, three above and three below	74%

Question 58.
Calculate the number of particles and unit cells in ‘x’ g of metallic crystal.
Answer:
Consider ‘x’ gram of a metallic crystal of molar mass M and density ρ. If the unit cell of the crystal has edge length ‘a’ then, volume of unit cell = a³.
Mass of one metal atom = \(\frac{M}{N_{\mathrm{A}}}\). If ‘n’ number of atoms are present in one unit cell then
Mass of unit cell = \(\frac{n \times M}{N_{\mathrm{A}}}\)
If ‘a’ is the edge length of the unit cell then, Volume of unit cell = a³
Density of unit cell = ρ = \(\frac{n \times M}{N_{\mathrm{A}}} \times \frac{1}{a^{3}}\)
∴ M = \(\frac{\rho \times N_{\mathrm{A}} \times a^{3}}{n}\)
∵ Molar mass M gram contains N_A particles
∴ x gram contains \(\frac{x \times N_{\mathrm{A}}}{M}\) particles.
Substituting the value M,

(i) Number of particles in x g crystal
= \(\frac{x \times N_{\mathrm{A}}}{\rho \times N_{\mathrm{A}} \times a^{3} / n}\)
= \(\frac{x \times n}{\rho \times a^{3}}\) particles

(ii) Number of unit cells in x g crystal :
∵ n particles are present in 1 unit cell
∴ \(\frac{x \times n}{\rho \times a^{3}}\) are present in, \(\frac{x \times n}{\rho \times a^{3}} \times \frac{1}{n}\)
= \(\frac{x}{\rho \times a^{3}}\) unit cells

(iii) Number of unit cells in V volume of crystal = \(\frac{V}{a^{3}}\)

Alternative method :
Consider ‘x’ g metal of atomic mass M g mol^-1.
Number of moles of metal = \(\frac{x}{M}\)
(a) Number of atoms (particles) of metal = \(\frac{x}{M} \times N_{\mathrm{A}}\)
(b) If unit cell contains ‘n’ atoms,
Number of unit cells = \(\frac{x}{M} \times \frac{N_{\mathrm{A}}}{n}\)
(c) If ‘a’ is the edge length then,
Volume of unit cells = a³
∴ Number of unit cells in V volume of crystal = \(\frac{V}{a^{3}}\).

Solved Examples 1.5 – 4.7

Question 59.
Solve the following :
[1 m = 10 dm = 100 cm = 10⁹ nm = 10¹² pm, 1Å = 10^-8 cm = 100 pm]

(1) A cubic unit cell of a crystal consists of atoms of A and B elements. Atoms of A occupy corners of the unit cell while one B atom is present at the body centre. Determine the formula of the crystalline compound.
Solution :
Given : Atoms of A are at the comers while atom B is at the body centre of the cubic unit cell.
Since \(\frac {1}{8}\)th atom is contributed at each comer and there are 8 comers in unit cell, number of atoms of A due to comers is \(\frac {1}{8}\) × 8 = 1.

In addition there is one atom of B at body centre. Hence this unit cell contains one atom of each, A and B, therefore the formula of the compound is AB.
Ans. The formula of the compound = AB.

(2) Atoms C and D form fee crystalline structure. Atom C is present at the corners of the cube and D is at the face centres of the cube. What is the formula of the compound ?
Solution :
Given : Crystal has fee structure.
Atoms C are at 8 comers while atoms D are at 6 face centres of the cubic unit cell.
At the comer, \(\frac {1}{8}\)th of each C atom is present while at each face centre, half of each D atom is present.
Number of C atoms = \(\frac {1}{8}\) × 8 = 1.
Number of D atoms = \(\frac {1}{8}\) × 6 = 3.
Thus unit cell contains one C atom and three D atoms.
Hence the formula of the compound is CD₃.
Ans. Formula of the compound = CD₃.

(3) A cubic unit cell contains atoms A at the corners, atoms B at face centres and atom C at the body centre. What is the formula of the crystalline compound?
Solution :
Given : Atoms A are at 8 comers, atoms B at the 6 face centres and one atom C at body centre.
Total number of atoms of A = \(\frac {1}{8}\) × 8 = 1.
Total number of atoms of B = \(\frac {1}{2}\) × 6 = 3.
One atom of C at the body centre.
Therefore the unit cell contains one atom of A, three atoms of B and one atom of C.
Hence the formula of the compound is AB₃C.
Ans. The formula of the crystalline compound is AB₃C.

(4) An element A and B constitute bcc type crystalline structure. Element A occupies body centre position and B is at the corners of cube. What is the formula of the compound? What are the coordination numbers of A and B ?
Solution :
Given : Crystalline structure is bcc type.
Atoms A are at 8 comers and atom B is at body centre.
∴ Number of atoms of A in a unit cell
= \(\frac {1}{8}\) × 8 = 1.
Number of atom B in a unit cell = 1.
Since unit cell contains one atom each of A and B, the formula of the compound is AB.
The coordination number of an atom A at comer is 8.
The coordination number of an atom B at body centre is 8.
Answer. Formula of the compound = AB.
Coordination number of A = 8
Coordination number of B = 8.

(5) Mention the number of atoms in the following unit cells :
(a) scc (b) bcc (c) fcc (d) hcp.
Answer:

Unit cell	Number of atoms
(a) scc	1
(b) bcc	2
(c) fcc	4
(d) hcp	3

(6) 0.1 mole of Buckminster fullerene of molar mass 720 gmol^-1 contains how many Kg of carbon ?
Solution :
Molar mass of fullerene, C60 = 720 gmol^-1
∵ Mass of 1 mole of fullerene = 720 g = 0.72 kg
∴ Mass of 0.1 mole of fullerene = 0.72 × 0.1
= 0.072 kg
Ans. 0.072 kg.

(7) In a cubic crystalline structure of zinc blende (ZnS), sulphide ions are at corners and face centres while zinc ions occupy half of tetrahedral voids.
Find in the unit cell :
(i) Number of Zn²⁺ ions
(ii) Number of S^2- ions
(iii) Number of ZnS molecules
(iv) Molecular formula of zinc blende.
Solution :
Given : S^2- ions are at 8 comers and 6 face centres.
Zn²⁺ ions occupy half of tetrahedral voids.
Number of S^2- ions in unit cell

= 1 + 3 = 4

Cubic unit cell has 8 tetrahedral voids. Since half of them are occupied by Zn²⁺ ions, there are 4Zn²⁺ ions in the unit cell.
Hence number of zinc sulphide (ZnS) molecules is 4.
Molecular formula of zinc blende is ZnS.
Ans. (i) Number of Zn²⁺ ions = 4
(ii) Number of S^2- ions = 4
(iii) Number of ZnS molecules = 4
(iv) Molecular formula of zinc blende = ZnS.

(8) In a crystalline compound, atoms A occupy ccp lattices while atoms B occupy 2/3 rd tetrahedral voids. What is the formula of the compound ?
Solution :
In ccp unit, lattice points are 8 comers and 6 face centres where atoms A are present.
∴ Number of A atoms

In cubic unit cell, there are 8 tetrahedral voids.
Hence,
Number of B atoms = \(\frac {2}{3}\) × 8 = \(\frac {16}{3}\).
Hence the formula should be A₄B_16/3 or A₁₂B₁₆ or A₃B₄.
Ans. The formula of the compound is A₃B₄.

(9) A compound forms hep structure. What is the number of (a) octahedral voids, (b) tetrahedral voids, (c) total voids formed in 0.2 mol of the compound?
Solution :
Number of atoms in 0.2 mol of the compound
= 0.2 × N_A = 0.2 × 6.022 × 10²³
= 1.2044 × 10²³ atoms
(a) Number of octahedral voids
= Number of atoms
= 1.2044 × 10²³

(b) Number of tetrahedral voids
= 2 × Number of atoms
= 2 × 1.2044 × 10²³
= 2.4088 × 10²³

(c) Total number of voids
= 1.2044 × 10²³ + 2.4088 × 10²³
= 3.6132 × 10²³
Ans. (a) Number of octahedral voids
= 1.2044 × 10²³
(b) Number of tetrahedral voids = 2.4088 × 10²³
(c) Total number of voids = 3.6132 × 10²³

(10) Copper crystallises into a fcc structure and the unit cell has length of edge 3.61 × 10^-8 cm. Calculate the density of copper. Atomic mass of copper is 63.5 g mol^-1.
Solution :
Given : Crystalline structure of Cu is fcc.
Edge length = a = 3.61 × 10^-8 cm
Atomic mass of Cu = 63.5 g mol^-1
Avogadro number = 6.022 × 10²³ mol^-1
Density = d = ?

In fcc structure, there are 8 Cu atoms at 8 comers and 6 Cu atoms at 6 face centres.
∴ Total number of Cu atoms
= \(\frac {1}{8}\) × 8 + \(\frac {1}{2}\) × 6 = 1 + 3
= 4
Mass of one Cu atom
= \(\frac{63.5}{6.022 \times 10^{23}}\) = 1.054 × 10^-22 g
∴ Mass of 4 Cu atoms = 4 × 1.054 × 10^-22
= 4.216 × 10^-22 g
Mass of unit cell = Mass of 4 Cu atoms
= 4.216 × 10^-22g
Volume of unit cell = a3 = (3.61 × 10^-8)3
= 4.7 × 10^-24 cm³
Density of unit cell = \(\frac{\text { Mass of unit cell }}{\text { Volume of unit cell }}\)
∴ ρ = \(\frac{4.216 \times 10^{-22}}{4.7 \times 10^{-23}}\) = 8.97 g cm^-3
Ans. Density of Cu = 8.97 g cm^-3.

(11) Niobium is found to crystallise with bcc structure and found to have density of 8.55 g cm^-3 (OR 8.55 kg m^-3). Determine the atomic radius of niobium if its atomic mass is 93.
Solution :
Given : Density of Niobium (Nb) crystal = 8.55 g cm^-3
Crystalline stmeture is bcc.
Atomic mass of Nb = 93 g mol^-1
Avogadro number = N_A = 6.022 × 10²³ mol^-1
Atomic radius of Niobium = ?
In bcc unit cell, there are 8 atoms at 8 comers and 1 atom at the body centre.
∴ Number of Nb atoms = \(\frac {1}{8}\) × 8 + 1 = 1 + 1 = 2.
Mass of one Nb atom = \(\frac{93}{6.022 \times 10^{23}}\) = 1.544 × 10^-22
∴ Mass of 2 Nb atoms = 2 × 1.544 × 10^-22 = 3.088 × 10^-22 g
Mass of unit cell
= Mass of 2Nb atoms = 3.088 × 10^-22 g
If a is edge length of bcc unit cell, volume of unit cell = a³

= 0.361 × 10^-22 cm³ = 36.1 × 10^-24 cm³
∴ a = (36.1 × 10^-24)^-1/3 = 3.3 × 10^-8 cm
If r is the radius of 1 Nb atom, then in bcc structure
r = \(\frac{\sqrt{3}}{4} a=\frac{\sqrt{3}}{4}\) × 3.3 × 10^-8
= 1.43 × 10^-8 cm
= 1.43 × 10^-10 m
= 1.43 × 10^-10 × 10⁹ nm
= 0.143 nm
Ans. Atomic radius of niobium atom = 0.143 nm

(12) Gold occurs as face centred cube and has a density of 19.30 kg dm^-3. Calculate atomic radius of gold. (Molar mass of Au = 197)
Solution :
Given : Density of Au = 19.3 kg dm^-3
Molar mass = 197 g mol^-1
Avogadro constant = N_A = 6.022 × 10²³ mol^-1
Atomic radius of Au = ?
In fcc unit cell, there are 8 atoms of Au at 8 comers and 6 atoms at 6 face centres.
Number of Au atoms in the unit cell = \(\frac {1}{8}\) × 8 + \(\frac {1}{2}\) × 6
= 4 atoms
Mass of 1 Au atom = \(\frac{197}{6.022 \times 10^{23}}\) = 3.271 × 10^-22 g
∴ Mass of 4 Au atoms = 4 × 3.271 × 10^-22 g = 1.308 g × 10^-21 g
∴ Mass of unit cell = 1.308 × 10^-21 g

= 6.777 × 10^-24 dm3
= 6.777 × 10^-23 cm3
∴ a = (6.777 × 10^-23)^1/3 = (67.77 × 10^-24)^-1/3
= 4.077 × 10^-8 cm
If r is the radius of Au atom, then for fcc unit cell,
r = \(\frac{a}{2 \sqrt{2}}\)
= \(\frac{4.077 \times 10^{-8}}{2 \sqrt{2}}\) = 1.442 x 10^-8 cm = 144.2 pm
Ans. Radius of Au atom = 144.2 pm.

(13) A compound is formed by two elements X and Y. The atoms of Y form ccp structure. The atoms of A occupy \(\frac {1}{3}\) of tetrahedral voids. Find the formula of the compound.
Solution :
In ccp structure, Y atoms are present at 8 comers and 6 face-centres of the ccp structure.

There are 8 tetrahedral voids of which \(\frac {1}{3}\)rd are occupied by atoms X. Hence unit cell has \(\frac {8}{3}\) atoms of X and 4 atoms of Y. The formula will be,
X_8/3 Y₄ or X₈Y₁₂ or X₂Y₃
Ans. Formula of the compound = X₂Y₃.

(14) A metal crystallises into two cubic faces namely face centered (FCC) and body centered (BCC), whose unit cell edge lengths are 3.5 Å and 3.0 Å respectively. Find the ratio of the densities of FCC and BCC.
Solution :
Given : Edge length of unit cell of fcc metal = 3.5 Å
= 3.5 × 10^-8 cm
Edge length of unit cell of bcc metal = 3 Å = 3 × 10^-8 cm
Density d = \(\frac{n \times \mathbf{M}}{a^{3} \times \mathbf{N}_{\mathrm{A}}}\)
where, n = Number of Fe atoms in the unit cell
M = Atomic mass of metal
a = Edge length of unit cell
N_A = Avogadro number
∴ For fcc unit cell = n = 4
For bcc unit cell = n = 2
∴ \(\frac{\text { Density of fcc unit cell }}{\text { Density of bcc unit cell }}=\frac{d_{\mathrm{fcc}}}{d_{\mathrm{bcc}}}\)

(15) The density of silver having atomic mass 107.8 gram mol^-1 is 10.8 gram cm^-3. If the edge length of cubic unit cell is 4.05 × 10^-8 cm, find the number of silver atoms in the unit cell. (N_A = 6.022 × 10²³, 1Å = 10^-8 cm)
Solution :
Given : d = 10.8 g cm^-3
M= 107.8 g mol^-1
a = 4.05 × 10^-8 cm
Number of Ag atoms in unit cell = n = ?
Mass of one Ag atom = \(\frac{107.8}{6.022 \times 10^{23}}\)
= 1.79 × 10^-22 g
If there are n atoms, then
Mass of unit cell = n × 1.79 × 10^-22 g
Volume of unit cell = a3 = (4.05 × 10^-8)³
= 6.643 × 10^-23 cm³

Ans. Number of silver atoms (Ag) atoms in unit cell = 4.

(16) Aluminium having atomic mass 27 g mol^-1 crystallises in face centred packed cubic crystal. Find the number of Al atoms in 10 g aluminium. How many unit cells will be present in it?
Solution :
Given : Atomic mass of Al = 27 g mol^-1
Mass of Al = 10 g
Avogadro number = N_A = 6.022 × 10²³ mol^-1
Number of Al atoms = ?
Number of unit cells = ?
1 gram atom of Al = 27 g Al contains 6.022 × 10²³
Al atoms
∴ Number of Al atoms in 10 g
= \(\frac{10 \times 6.022 \times 10^{23}}{27}\)
= 2.23 × 10²³
In fcc structure, each unit cell contains 4Al atoms.
∴ Number of unit cells = \(\frac{2.23 \times 10^{23}}{4}\)
= 5.575 × 10²²
Ans. Number of Al atoms = 2.23 × 10²³
Number of unit cells = 5.575 × 10²².

(17) The density of iron crystal is 8.54 gram cm^-3. If the edge length of unit cell is 2.8 Å and atomic mass is 56 gram mol^-1, find the number of atoms in the unit cell. What is the type of crystal ?
Solution :
Given :
Density of Fe crystal = d = 8.54 g cm^-3
a = 2.8 Å = 2.8 × 10^-8 cm
Atomic mass = M = 56 g mol^-1
Number of atoms in unit cell, n = ?
Mass of one atom = \(\frac{56}{6.022 \times 10^{23}}\) = 9.3 × 10^-23 g
Volume of unit cell = a³ = (2.8 × 10^-8)³
= 2.195 × 10^-23 cm³
If there are n atoms in the unit cell, then
Mass of unit cell = n × 9.3 × 10^-23 g

Since unit cell contains 2 atoms, the crystal has bcc structure.
Ans. Number of atoms in unit cell = 2
Type of crystal = bcc

Question 60.
What is meant by crystal defects or imperfections?
Answer:

1. Defect in crystalline structure : Any deviation from orderly and stoichiometrically perfect arrangement of atoms, ions or molecules in the crystal lattice is called a defect in the crystalline structure.
2. Defects are created during the crystallisation process. If the process occurs at faster rate, the defects are more.
3. The properties of solids are affected due to imperfactions.

Question 61.
Mention the types of defects in the solids or crystal structures.
Answer:
The defects in crystalline solids are of two types viz., (1) Point defect and (2) Line defect.
(1) Point defects are further classified as :
(a) Vacancy defect or Schottky defect
(b) Interstitial defect or Frenkel defect
(c) Impurity defect :

This is further classified as

• Substitution impurity defect
• Interstitial impurity defect.

(2) Line defects are further classified as

• Edge dislocation
• Screw dislocation.

Question 62.
What are point defects?
Answer:
Point defects : These defects arise due to irregularities produced in the arrangement of basis of lattice points in crystalline solids.

Question 63.
What are major classes of point defects ?
Answer:
There are three major classes of point defects : stoichiometric point defects, impurity defects and nonstoichiometric point defects.

There are four types of stoichiometric point defects as vacancy defect, self interstitial defect, Schottky defect and Frenkel defect.

Question 64.
Explain vacancy defect.
Answer:
Vacancy defect :
(1) During crystallisation, some of regular sites in solid remain unoccupied and the missing particle creates a vacancy defect.
(2) The defect can be developed by heating the substance.

(3) The mass of solid decreases due to absence of particles in regular sites.
(4) Since the volume remains the same the density of the substance decreases.

Question 65.
Explain self interstitial defect in elemental solid.
Answer:
Self Interstitial defect in elemental solid : The empty spaces or voids in between the particles at lattice points represent interstitial defective sites or self interstitial defects.

This defect arises in the following two ways :
(1) An extra particle occupies the empty interstitial space. This extra particle is similar to those already present in the crystal.

(2) (i) A particle gets shifted from its original regular site to an empty interstitial space in the crystal.

(ii) This displacement of a particle produces a vacancy defect at its regular site.
(iii) This defect is referred to as a combination of vacancy defect and self interstitial defect.
(iv) Since there is neither loss or gain in mass of the substance, the density of it remains unchanged.

Question 66.
How does Schottky defect arise?
Answer:
(1) Schottky defect arises in ionic solids due to missing of equal number of cations and anions from their regular positions in the crystal lattice creating vacancies.

(2) There arises formation of two holes per loss of ion pair.

(3) Conditions for formation of Schottky defect :
Characteristics of ionic solids showing Schottky defect :

• High degree of ionic character
• High coordination number of anion
• Small difference between ionic size or radii of cation and anion. The ionic ratio \(\frac{r_{\text {cation }}}{r_{\text {anion }}}\) is not below unity.

Question 67.
How does Frenkel defect arise?
Answer:

• Frenkel defect : This defect arises when an ion of an ionic compound is missing from its regular site and occupies interstitial vacant position between lattice points.
• Cations have smaller size than anions, hence generally cations occupy the interstitial sites.
• This creates a vacancy defect at its original position and interstitial defect at new position.
• Frenkel defect is regarded as the combination of interstitial defect and vacancy defect.

Conditions for the formation of Frenkel defect :

• This defect arises in ionic compounds with a large difference between the sizes of cation and anion.
• The ionic compounds must have ions with low coordination number.

Question 68.
What are the consequences of Frenkel defect ?
Answer:
Consequences of Frenkel defect :

• Since there is no loss of ions from the crystal lattice, the density of the solid remains unchanged.
• The crystal remains electrically neutral.
• This defect is observed in ZnS, AgCl, AgBr, AgI, CaF₂, etc.

Question 69.
Explain nonstoichiometric defect.
Answer:
Nonstoichiometric defect : This defect arises when the ratio of number of one kind of atoms to that of other kind of atoms (or ratio of number of cations to anions) becomes different from the actual stoichiometric formula. This involves the change in stoichiometry of the compound.

There are two types of nonstoichiometric defects as follows :
(1) Metal deficiency defect : This defect arises in compounds of metal which show variable oxidation states. In some metal crystals, positive metal ions are missing from their regular lattice sites. The extra negative charge is balanced by cations of the same metal with higher oxidation state than that of missing cation at site.

Consider a crystal of NiO. When one Ni²⁺ is missed from its lattice point, it creates a vacant site.

The deficiency of two positive charges is compensated by two Ni³⁺ ions at other lattice points of Ni²⁺ ions and the composition of NiO crystal becomes Ni_0.97O_1.0.

(2) Metal excess defect : There are two types of metal excess defect as follows :
(a) Presence of a neutral atom or an extra positive ion at interstitial position :

There are two types or ways of metal excess defects in ZnO. In the first case, Zn atom is present in the interstitial space as shown in figure.

(b) Metal ions and electrons at interstitial sites :
The second case arises when ZnO is heated, Zn²⁺ and electrons are obtained,

The excess Zn²⁺ ions are trapped in interstitial sites in the crystal lattice. Electrons occupy interstitial sites by diffusing into the interstitial sites.
In above both cases, the nonstoichiometric formula of ZnO is Zn_{1 + x} O_1.0

Question 70.
Explain defects due to anion vacancies.
OR
Explain colour of crystals or F centres.
Answer:

• The defect due to anion vacancies imparts colour to the colourless crystal.
• When a colourless crystal of NaCl is heated in the atmosphere of sodium vapour, the sodium atoms are deposited on the crystal surface.
• Due to diffusion of Cl^– ions to the crystal surface vacancies are created at their regular sites.
• These diffused Cl^– ions combine with Na atoms on the surface forming NaCl along with releasing electrons from sodium atoms. Na + Cl^– → NaCl + e^–

The released electrons diffuse into the crystal and occupy vacant sites of anions Cl^– in the crystal.
The anion vacant sites occupied by electrons are called F-centres or colour centres. Due to colour centres NaCl shows yellow colour.
Now NaCl crystal has excess of Na atoms having nonstoichiometric formula Na_1+x Cl_1.0.

Question 71.
How are solids classified according to electrical conductivity?
Answer:
According to electrical conductivity, solids are classified as follows :
(1) Conductors :

• The solids having electrical conductivity in the range of 10⁴ to 10⁷ Ohm^-1m^-1 are called conductors.
• The examples of conductors are metals and electrolytes.
• Electrical conductivity in metals is due to free movement of electrons while electrolytes conduct electricity due to migration ions.

(2) Insulators :

• Solids having very low electrical conductivity in the range of 10^-20 to 10^-10 Ohm^-1 m^-1 are called insulators.
• The examples of insulators are nonmetals and molecular solids.

(3) Semiconductors :

• Solids having conductivity in the range of 10^-6 to 10⁴ Ohm^-1m^-1 are semiconductors.
• The conductivity range is intermediate between conductors and insulators.
• The examples of semiconductors are silicon and germanium.

Question 72.
Explain band theory.
OR
Explain the origin of electrical properties in solids.
Answer:
(1) Metals are good conductors of heat and electricity. This is explained on the basis of band theory which involves the presence of free electrons.

(2) According to band theory, the atomic orbitals of metal atoms overlap to form molecular orbitals which are spread all over the crystal structure.

(3) The energy difference between adjacent molecular orbitals decreases as the number of molecular orbitals increases and when it becomes very less, the orbitals merge into one another forming continuous bands which extent over the entire crystal.

(4) There are two types of bands of molecular orbitals as follows :

• Valence band : The atomic orbitals with filled electrons from the inner shells form valence bands, where there are no free mobile electrons since they are involved in bonding.
• Conduction band : Atomic orbitals which are partially filled or empty on overlapping form closely placed molecular orbitals giving conduction bands where electrons are delocalised and can conduct, heat and electricity.

(5) Band gap :

• The energy difference between valence band and conduction band is called band gap.
• Band gap decides whether electrons from valence band can be promoted to vacant conduction band or not.
• The conductors like metals have very small or no band gap and electron can be promoted by thermal energy. The nonconductors have large band gap. The insulators have very large band gap.

Question 73.
Metals are good conductors of electricity. Explain.
Answer:
(1) Metals are good conductors of electricity since the outermost electrons of atoms in metallic crystal occupy conduction bands.

(2) The number of electrons in conduction bands is very large.
(3) The conduction bands in metals can be labelled as ‘s’ band, overlapping s and p bands etc. according to overlapping of orbitals.
(4) This results in delocalisation of outermost electrons forming metal ions. Hence, this is analogous to metal cations immersed in the sea of electrons.

Question 74.
Why does metallic conductivity decrease by increasing temperature?
Answer:

1. In metals a large number of outermost electrons of atoms occupy conduction bands.
2. Band formation in metals results in delocalisation of outermost electrons forming metal ions or cations.
3. The metallic cations occupying crystal lattice sites vibrate about mean positions.
4. As temperature increases the vibrational motion increases which interrupts flow of electrons decreasing electrical conductivity.

Question 75.
Explain insulators.
Answer:
(1) In insulators the valence band is completely filled by electronics while conduction band is empty.

(2) The energy gap between valence band and conduction band in insulator is very large.
(3) Thermal energy is not sufficient to promote electrons from valence band to conduction band.
(4) Therefore, the conduction band in insulator remains vacant and does not allow the conduction of electricity.

Question 76.
What are semiconductors ? Mention the types of semiconductors.
Answer:
(1) Semiconductors : The substances like silicon, germanium which have poor electrical conductance at low temperature but the conductance increases with the increase in temperature are called semiconductors.

(2) Their conductivity lies between metallic conductors and insulators.
(3) The energy difference between valence band and conduction band is relatively small, hence the electrons from valence band can be excited to conduction band by heating.

(4) Types of semiconductors : There are two types of semiconductors :
(a) Intrinsic semiconductor
(b) Extrinsic semiconductor

(a) Intrinsic semiconductor :

• A pure semiconductor material like pure Si, Ge which have a very low but finite electrical conductivity is called intrinsic semiconductor.
• The electrical conductivity of a semiconductor increases with the increase in temperature.

(b) Extrinsic semiconductor :

• Semiconductor doped with different element is called extrinsic semiconductor.
• By doping with elements like Ga or P, the electrical conductivity is increased.

Question 77.
Explain extrinsic semiconductor and doping.
Answer:
(1) A semiconductor obtained by doping intrinsic semiconductor with elements of third group and fifth group is called extrinsic semiconductor.
(2) This extrinsic semiconductor has higher electrical conductivity than pure intrinsic semiconductor.

(3) There ate two types of extrinsic semiconductors:
(A) n-type semiconductors:
(i) n-type semiconductor contains increased number of electrons in the conduction band.
(ii) When Si semiconductor is doped with 15th group element phosphorus, P, the new atoms occupy some vacant sites in the lattice in place of Si atoms.

(iii) P has five valence electrons, out of which four are involved in covalent bonding with neigh-bouring Si atoms while one electrons remains free and delocalised.
(iv) These free electrons increase the electrical conductivity of the semiconductor.
(v) The semiconductors with extra non-bonding free electrons are called n-type semiconductors.

(B) p-type semiconductor :
(i) p-type semiconductor is obtained by doping a pure semiconductor by an element of 13th group like B.
(ii) 13th group element has less number of valence electrons. When pure Si is doped with B atoms, these atoms occupy Si lattice points.

(iii) Boron (₅B) has only 3 valence electrons which form covalent bonds with the neighbouring Si atoms, while one bond has shortage of one electron.
(iv) This creates a vacancy or a hole, hence the electron from neighbouring Si atom jumps into this hole creating a vacancy in itself. This process continues, i.e., positive holes move in one direction while electrons moves in opposite direction.
(v) Due to electron deficient positions, this semiconductor is called p-type semiconductor.
(vi) When p-type semiconductor is connected to the external source of electricity, electrons from neighbouring silicon atoms jump into the holes so that electrons move towards positive electrode and holes migrate towards negative electrode.
(vii) Hence electrical conduction in p-type semiconductor is due to electrons and holes.

Question 78.
What are the uses of semiconductors ?
Answer:
The uses of semiconductors are as follows :

1. They are used in transistors, digital computers and cameras.
2. They are used in solar cells and television sets.
3. By combining n-type and p-type semiconductors, n-p junctions are formed which are effectively used in rectifiers or to convert light energy into electrical energy.

Question 79.
Classify the following semiconductors into n or p-type.
(i) B doped with Si
(ii) As doped with Si
(iii) P doped with Si
(vi) Ge doped with In.
Answer:

Semiconductor	Type
(i) B doped with Si	p-type
(ii) As doped with Si	n-type
(iii) P doped with Si	n-type
(iv) Ge doped with In	p-type

Question 80.
Explain the origin of magnetic properties in solids.
Answer:
(1) The magnetic properties of a substance arise due to the presence of electrons in their atoms or molecules.

(2) The electrons while revolving around the nucleus in various orbits, also spin around their own axes. Both these motions of electrons result in generating magnetic field and magnetic moments. Hence electron be haves as a tiny magnet.

(3) An atomic orbital can accommodate maximum two electrons with opposite spins, clockwise and anticlockwise. The degenerate orbitals like p, d and f orbitals can accommodate electrons with same spins until they are half filled.

(4) When a substance contains one or more unpaired electrons spinning in same direction, then their magnetic moments and magnetic properties add and the substance is said to be paramagnetic.

If a substance contains all electrons paired then their spins are balanced and magnetic moments and magnetic properties are cancelled and the substance is said to be diamagnetic.

Question 81.
Explain diamagnetism.
Answer:
(1) The magnetic properties of a substance arise due to presence of the electrons.

(2) An electron while revolving around the nucleus, also spins around its own axis and generates a magnetic moment and a magnetic property.

(3) If an atom or a molecule of the substance contains all electrons paired, spinning clockwise and anticlockwise, their magnetic moments and magnetic properties get cancelled. Hence they oppose and repel the applied magnetic field. This phenomenon is called diamagnetism and the substance is said to be diamagnetic.
For example : Zn, Cd, H₂O, NaCl, etc.

Multiple Choice Questions

Question 82.
Select and write the most appropriate answer from the given alternatives for each subquestion :

1. A substance which on cutting will give irregular cleavage is
(a) glass
(b) KBr
(c) ZnS
(d) NaCl
Answer:
(a) glass

2. A solid which has definite heat of fusion is
(a) plastic
(b) CaCl₂
(c) glass
(d) soda lime glass
Answer:
(b) CaCl₂

3. In solids the constituent particles may be
(a) atoms
(b) ions
(c) molecules
(d) any one of the above three
Answer:
(d) any one of the above three

4. A single substance that exists in two or more forms is called
(a) polymorphous
(b) amorphous
(c) isomorphous
(d) monomorphous
Answer:
(a) polymorphous

5. Graphite is a
(a) metallic crystal
(b) covalent crystal
(c) ionic crystal
(d) molecular crystal
Answer:
(b) covalent crystal

6. Anisotropy is observed in
(a) Pyrex glass
(b) plastic
(c) K₂SO₄
(d) fullerene
Answer:
(c) K₂SO₄

7. The number of crystal systems (or types) is
(a) 4
(b) 7
(c) 8
(d) 12
Answer:
(b) 7

8. The number of Bravais lattices are
(a) 6
(b) 8
(c) 12
(d) 14
Answer:
(d) 14

9. Face centred cubic crystal is
(a) Cubic lattice of Bravais system
(b) Bravais lattice of HCP
(c) Bravais lattice of cubic system
(d) Cubic lattice with 5 atoms
Answer:
(c) Bravais lattice of cubic system

10. The number of tetrahedral sites per sphere in ccp structure is,
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(b) 2

11. The packing fraction for a body centred cubic structure is
(a) 0.42
(b) 0.53
(c) 0.68
(d) 0.82
Answer:
(c) 0.68

12. If r is the radius of an atom and a is an edge length of fcc unit cell, then
(a) r = \(\frac{\sqrt{3}}{4} a\)
(b) r = \(\frac{a}{2 \sqrt{2}}\)
(c) r = \(\frac{a}{2}\)
(d) r = \(2 \sqrt{2} a\)
Answer:
(b) r = \(\frac{a}{2 \sqrt{2}}\)

13. The ratio of packing efficiency in see, bcc and fee crystalline structures is
(a) 1 : 1.2 : 1.3
(b) 1 : 1.12 : 1.23
(c) 1 : 1.3 : 1.4
(d) 1 : 1.25 : 1.38
Answer:
(c) 1 : 1.3 : 1.4

14. The correct sequence of the atomic layers in cubic close packing is
(a) ABABA
(b) ABACABAC
(c) ABCABC
(d) AABBAABB
Answer:
(c) ABCABC

15. The major binding force in diamond is
(a) Covalent bond
(b) Ionic bond
(c) Metallic bond
(d) Coordinate covalent bond
Answer:
(a) Covalent bond

16. The ratio of close packed atoms to octahedral holes in cubic packing is
(a) 1 : 1
(b) 1 : 2
(c) 2 : 1
(d) 1 : 3
Answer:
(a) 1 : 1

17. A defect present in AgCl is
(a) Frenkel defect
(b) Schottky defect
(c) point defect
(d) interstitial impurity defect
Answer:
(a) Frenkel defect

18. An ionic solid crystallises in bcc structure. If the ionic radii of cation and anion are 0.84 Å and 1.07 Å, the length of the body diagonal is
(a) 1.91 Å
(b) 2.75 Å
(c) 3.82 Å
(d) 2.32 Å
Answer:
(c) 3.82 Å

19. The type of defect in NaCl crystal will be
(a) point defect
(b) interstitial defect
(c) vacancy defect
(d) impurity defect
Answer:
(c) vacancy defect

20. Schottky defects are observed in which solid among the following ?
(a) Brass
(b) Cesium chloride
(c) Zinc sulphide
(d) Stainless steel
Answer:
(b) Cesium chloride

21. An ionic compound crystallises in FCC type structure with ‘A’ ions at the centre of each face and ‘B’ ions occupying comers of the cube. The formula of compound is
(a) AB₄
(b) A₃B
(c) AB
(d) AB₃
Answer:
(b) A₃B

22. Total number of different primitive unit cells are
(a) 6
(b) 7
(c) 12
(d) 14.
Answer:
(d) 14

23. The volume of atoms present in body centred cubic unit cell of a metal of atomic radius r is,
(a) \(\frac{16}{3} \pi r^{3}\)
(b) \(\frac{8}{3} \pi r^{3}\)
(c) \(\frac{12}{3} \pi r^{3}\)
(d) \(\frac{24}{3} \pi r^{3}\)
Answer:
(b) \(\frac{8}{3} \pi r^{3}\)

24. The substances which can be permanently magnetised are
(a) diamagnetic
(b) paramagnetic
(c) ferromagnetic
(d) non-magnetic
Answer:
(c) ferromagnetic

25. CrO₂ is
(a) diamagnetic
(b) paramagnetic
(c) metalic
(d) ferromagnetic
Answer:
(d) ferromagnetic

26. A metallic element crystallises in face centred cubic structure. If the radius of metal ion is 0.92 Å, the edge length of the unit cell of the crystal is
(a) 0.8464 Å
(b) 1.252 Å
(c) 5.187 Å
(d) 2.6 Å
Answer:
(d) 2.6 Å

27. The volume of unit cell of a metallic crystal of bcc type is 8.4 × 10^-23 cm³. The volume occupied by 10 atoms in the crystalline structure is
(a) 4.2 × 10^-22 cm³
(b) 3.12 × 10^-23 cm³
(c) 1.74 × 10^-23 cm³
(d) 2.856 × 10^-22 cm³
Answer:
(d) 2.856 × 10^-22 cm³

28. Copper crystallises in face centred cubic structure. If the unit cell length is 360 pm, the radius of copper atom is
(a) 180 pm
(b) 156 pm
(c) 127 pm
(d) 110 pm
Answer:
(c) 127 pm

29. If all the lattice points in ccp structure namely comers, face and edge centres and body centre are occupied by atoms then the total number of atoms in the unit cell will be
(a) 8
(b) 12
(c) 14
(d) 16
Answer:
(a) 8

30. Gold crystallises in face centred cubic structure. If atomic mass of gold is 197 g mol^-1, the mass of the unit cell of gold will be
(a) 3.25 × 10^-23 kg
(b) 6.5 × 10^-23 kg
(c) 3.9 × 10^-24 kg
(d) 1.3 × 10^-24 kg
Answer:
(d) 1.3 × 10^-24 kg

31. The mass of a unit cell of a body centred cubic crystal of a metal is 72.2 × 10^-23 g. The atomic mass of the metal is
(a) 128.6 gmol^-1
(b) 108.7 gmol^-1
(c) 217.3 gmol^-1
(d) 57.86 gmol-1
Answer:
(c) 217.3 gmol^-1

32. An element crystallises in fee structure. If the atomic mass of the element is 72.7 U, the mass of one unit cell of it will be
(a) 2.9 × 10^-24 g
(b) 4.83 × 10^-25 kg
(c) 1.2 × 10^-22 g
(d) 2.41 × 10^-24 kg
Answer:
(b) 4.83 × 10^-25 kg

33. Edge length of a cubic unit cell is 354 pm. The distance between two atoms diagonally opposite on the face is
(a) 500 pm
(b) 354 pm
(c) 708 pm
(d) 627 pm
Answer:
(a) 500 pm

34. The unit cell has an edge length 403 pm. The distance between two atoms placed opposite ends of body diagonal will be
(a) 806 pm
(b) 201.5 pm
(c) 698 pm
(d) 578 pm
Answer:
(c) 698 pm

35. An element having atomic mass 115 u, crystallises in bcc structure. The number of unit cells in 1 g of the element will be
(a) 2.6 × 10²¹
(b) 3.8 × 10²³
(c) 8.7 × 10^-3
(d) 6.17 × 10²⁰
Answer:
(a) 2.6 × 10²¹

36. The edge length of a bcc unit cell of a metallic crystal is 2.9 Å. Hence the diameter of an atom is
(a) 1.025 Å
(b) 2.512 Å
(c) 1.45 Å
(d) 1.31 Å
Answer:
(b) 2.512 Å

37. An element crystallises in fee structure. If the atomic radius is 130 pm, the edge length of unit cell is
(a) 332.5 pm
(b) 410 pm
(c) 390 pm
(d) 367.6 pm
Answer:
(d) 367.6 pm

38. The arrangement of layers in hexagonal close packing is
(a) ABCABC
(b) ABAB
(c) ABBABBA
(d) ABBCABBC
Answer:
(b) ABAB

39. For square close packing, the planar arrangement is
(a) AAAA
(b) ABAB
(c) ABCABC
(d) AABBAA
Answer:
(a) AAAA

40. Semiconductors are manufactured by addition of impurities of
(a) p-block elements
(b) actinoids
(c) Lanthanoids
(d) s-block elements
Answer:
(a) p-block elements

41. p-type semiconductor is formed when trace amount of impurity is added to silicon. The number of valence electrons in the impurity atom must be
(a) 3
(b) 5
(c) 1
(d) 2
Answer:
(a) 3

42. n-type semiconductor is formed when trace amount of impurity is added to silicon. The number of valence electrons in the impurity atom must be
(a) 3
(b) 5
(c) 1
(d) 2
Answer:
(b) 5

Balbharti Maharashtra State Board Class 12 History Important Questions Chapter 11 India Transformed Part 1 Important Questions and Answers.

Maharashtra State Board 12th History Important Questions Chapter 11 India Transformed Part 1

1A. Choose the correct alternative and rewrite the statement.

Question 1.
On 1st January 1995, 123 nations together founded an organisation known as ____________
(a) United Nations Organisation (UNO)
(b) World Trade Organisation (WTO)
(c) SEATO
(d) I.C.A.R.
Answer:
(b) World Trade Organisation (WTO)

Question 2.
In 1998, with a view to provide support to farmers in difficult times, ____________ plan was started.
(a) Kisan Credit Card
(b) Kisan Housing Plan
(c) Kisan Employment Card
(d) National Farmer’s Bank
Answer:
(a) Kisan Credit Card

Question 3.
Under ____________ scheme, each family in rural areas was given assurance of at least 100 day’s work.
(a) Agriculture and Livestock Scheme
(b) Pradhan Mantri Peek Vima Yojana
(c) Jawahar Gram-Samruddhi Yojana
(d) Rashtriya Gramin Rojgar Hami Yojana
Answer:
(d) Rashtriya Gramin Rojgar Hami Yojana

Question 4.
____________ ranks the first in fish production while ____________ ranks the second.
(a) China, Turkey
(b) India, China
(c) India, Brazil
(d) China, India
Answer:
(d) China, India

Question 5.
The Government of India, knowing the importance of having roads in good conditions in the interior areas, started ____________ in 2000.
(a) Pradhan Mantri Gram Sadak Yojana
(b) National Highway Plan
(c) Golden Quadrilateral
(d) Metro Railway
Answer:
(a) Pradhan Mantri Gram Sadak Yojana

Question 6.
The 11th conference of BRICS was organised in ____________
(a) India
(b) China
(c) Brazil
(d) South Africa
Answer:
(c) Brazil

Question 7.
In 2008, India launched ____________ the first lunar probe.
(a) Aaryabhatt I
(b) Chandrayaan 1
(c) Mangalyan
(d) Earth 2
Answer:
(b) Chandrayan 1

Question 8.
In 1946, ‘United Nations’ declared the ____________ to be the fundamental human right.
(a) Right to Information
(b) Right to Freedom
(c) Right to Speech and Expression
(d) Right to Mercy
Answer:
(a) Right to Information

Question 9.
In 1990, ____________ started the movement called as ‘Majdoor Kisan Shakti’.
(a) Medha Patkar
(b) Arimdhati Roy
(c) Aruna Roy
(d) L.K. Kulwal
Answer:
(c) Aruna Roy

Question 10.
In 2001, ____________ started a movement in Maharashtra in support of ‘Right to Information’ Act.
(a) Anna Hazare
(b) Rahi Sarnobat
(c) Aruna Roy
(d) Arvind Kejriwal
Answer:
(a) Anna Hazare

Question 11.
The state of Jammu-Kashmir and Ladakh was given a special status by ____________ of the Constitution of India.
(a) Article 356
(b) Preamble
(c) Article 375
(d) Article 370
Answer:
(d) Article 370

Question 12.
In 1947, ____________ established ‘Jammu Praja Parishad’ party.
(a) Prem Nath Dogra
(b) Dr. Shyama Prasad Mukherjee
(c) Omar Abdulla
(d) Atal Bihari Vajpayee
Answer:
(a) Prem Nath Dogra

1B. Find the incorrect pair from group ‘B’ and write the corrected one.

Question 1.

Group ‘A’	Group ‘B’
(a) Telangana	Telangana Rashtriya Samiti
(b) Jammu-Kashmir	Jammu Praja Party
(c) Jharkhand	Bhartiya Jharkhand Parishad
(d) Uttarakhand	Uttarakhand Parvatiya Rajya Parishad

Answer:
Jharkhand – All India Jharkhand Party

2A. Write the names of historical places/persons/events.

Question 1.
The Director of WTO who prepared a draft for the establishment of this organisation –
Answer:
Arthur Dunkel

Question 2.
This plan was launched by merging together ‘Rojgar Aashwasan Yojana’ and ‘Jawahar Gram-Samruddhi Yojana’ –
Answer:
Sampoorna Gramin Rojgar Yojana

Question 3.
The scheme which is implemented for the economic welfare of the farmer –
Answer:
Pradhan Mantri Vima Yojana

Question 4.
The programme which was launched for massive modernisation of cities in 2005 –
Answer:
Jnnurm-Jawaharlal Nehru National Urban Renewal Mission

Question 5.
The service which changed the very nature of the Indian Postal Service –
Answer:
Speed Post

Question 6.
Its mathematical potential was enormous because of which India entered the global computer market –
Answer:
Param-10000

Question 7.
The place where India conducted underground nuclear test two times to prove its nuclear strength –
Answer:
Pokhran in Rajasthan

Question 8.
The first female scientist to be elected as the General President of the 62nd Indian Science Congress Association –
Answer:
Asima Chatterjee

Question 9.
The war which was fought between India and Pakistan over the issue of intrusion of Pakistan military forces in Ladakh –
Answer:
Kargil War

Question 10.
The name of the operation given to the Kargil War –
Answer:
Operation Vijay

Question 11.
The first nuclear submarine was built in India –
Answer:
Strategic Strike Nuclear Submarine of Arihant Class

2B. Choose the correct reason from those given below and complete the sentence.

Question 1.
Several plans for rural development have been implemented, so that ____________
(a) the rural sector should not get neglected and the balance between rural and urban development be maintained
(b) the rural sector becomes richer than urban areas
(c) people could donate money for the development of the rural sector
(d) rural sector becomes richer than urban sector
Answer:
(a) the rural sector should not get neglected and the balance between rural and urban development be maintained

Question 2.
Rojgar Hami Yojana was started by the ‘Ministry of Commerce and Industry of the Government of India ____________
(a) to provide employment to urban youth
(b) to give pension to the retired army personnel
(c) to assure daily wages to the unemployed agricultural labourers
(d) to increase the employment rate in tribal areas
Answer:
(c) to assure daily wages to the unemployed agricultural labourers

Question 3.
The Government of India established a separate ‘Ministry of Disinvestment’ ____________
(a) to give credits to private firms
(b) to show sympathy towards private firms
(c) to invest more money in the government sector
(d) to take care of its disinvestment policy, i.e. the gradual withdrawal of governmental investment in the public sectors
Answer:
(d) to take care of its disinvestment policy, i.e. the gradual withdrawal of governmental investment in the public sectors

3. Complete the following concept map.

Question 1.

Answer:

Question 2.

Name of the State	Date of Formation
1. ………………….	1st November 2000
2. Uttarakhand	…………………………
3. ………………….	15th November 2000
4. Telangana	………………………….
5. Jammu-Kashmir	31st October 2019
6. Ladakh	………………………….

Answer:

Name of the State	Date of Formation
1. Chhattisgarh	1st November 2000
2. Uttarakhand	9th November 2000
3. Jharkhand	15th November 2000
4. Telangana	2nd June 2014
5. Jammu-Kashmir	31st October 2019
6. Ladakh	31st October 2019

4A. Write short notes.

Question 1.
BRICS
Answer:

• This organisation was established in 2006. Its name is formed by adopting the first letter of the names of the participant countries. The participant members are Brazil, Russia, India, China, and South Africa.
• This organisation was established with an aim of enhancing trade among these countries.
• The 11th conference of BRICS was organised in Brazil. The theme of this conference was ‘Economic Growth for an Innovative Future’.
• Subjects like technological co-operation, technology, and innovation, digital economy, international crime, financial scams were discussed.

Question 2.
GATT
Answer:

• During the times of the Second World War, many countries had adopted the policy of imposing various duties and taxes on imported goods, with a view to protecting their home markets.
• It resulted in declining in trade. A meeting was called in Cuba to discuss this problem, which was attended by 56 nations.
• It was decided to establish a permanent organisation to resolve the problems related to international trade. A legal agreement was signed by 23 nations on 30th October 1947, which is known as GATT. This agreement was the first multinational trade agreement.
• GATT gave priority to economic development through production and trade, to treat the member nation as ‘most favoured nation’.
• An annual meeting of the member countries of GATT used to be held in Geneva. It was attended by the representative of the member countries.
• Each country is entitled to one vote. Problems faced by individual nations regarding the difficulties of international trade were discussed in the meeting and the decision was based on these discussions.
• Later GATT became a part of the ‘World Trade Organisation’.

Question 3.
World Trade Organisation
Answer:

• On 1st January 1995, 123 nations together founded an organisation with the objective of opening the world for free trade. It was called World Trade Organisation (WTO). It’s a global trade organisation and India is a member of it.
• Arthur Dunkel, the Director-General of WTO, prepared a draft which has been fundamental to the establishment of the organisation. This draft is known as ‘Dunkel Draft’.
• The crux of this draft emphasis on trade is free from governmental custom duty and other restrictions. This approach is known as ‘liberalisation’.
• All participating countries agreed upon a set of rules and a premise common to all that would promote international trade.
• Provisions were made in the spheres of grants, exports-imports, foreign investments, reserved sectors, agriculture, technology, and the service sector.
• After becoming a member of WTO, India put a thrust on economic progress. The contribution of Prime Minister Narsimha Rao, Atal Bihar Vajpayee, and Manmohan Singh is very important in this aspect.
• The report published in 2006 has made a special mention of the increasing economic growth rate of India.

Question 4.
VVPAT
Answer:

• VVPAT means Voter Verified Paper Audit Trail.
• The Government of India started using this machine for the Nagaland Assembly Election in 2011.
• Since 2019, this device has been widely used for the Lok Sabha elections. The slip generated by the machine can be checked to determine whom you voted for.
• The voter sees the slip a few seconds after the vote. The voter can confirm his or her own vote through this machine.

Question 5.
Indian Science Congress Association.
Answer:

• This association was established on 15th January 1914 with the objective of promoting the scientific environment in India and publishing dissertations, research papers, and periodicals.
• In 1975, Asima Chatterjee became the first female scientist to be elected as the General President of the 62nd Indian Science Congress Association.

Question 6.
Speed Post
Answer:

• The Indian postal department started the service of speed post in 1986 which changed the nature of post service.
• This service was used by the majority of Indians, more than three crore letters and parcels were delivered from this service.
• The customer will get the message of successful delivery of their items.
• The postal department now offers courier services like passport delivery, business parcels, cash-on-delivery, logistics posts, and air freights.
• The post office even offers a packaging service. Over one lakh and fifty thousand post offices are offering the services like paying bills, sending festive cards and other objects.
• Since 2016, the postal department has started service of delivering Ganges water from Rishikesh and Gangotri at personal addresses.
• Buying personalized postage stamps with personal photographs and special schemes for philatelists are also available at ‘Post Shops’ opened at 80 post offices.

4B. Explain the following statements with reasons.

Question 1.
The service of ‘Speed Post’ changed the very nature of the Indian Postal Service.
Answer:

• The service of ‘Speed Post’ was started by the Indian Postal Department’ in 1986. Many people take advantage of this service, to the tune of more than three crores of letters and parcels is being delivered every month.
• The postal department sends a message of successful delivery on the mobile phone of the sender. This facility has made the speed post service more reliable.
• In addition, the postal department now offers courier services like delivery of passport, business parcel, cash-on-delivery, logistics post, and air freights.
• Now the post office offers the packaging service at an extra charge. This has increased the business of the postal department.
• It also offers services like paying various bills, sending festive greetings cards, and similar objects. The postal department has started a very novel service since 2016 of delivering Ganges water (Ganga Jal) at personal addresses from Rishikesh and Gangotri.
• Along with its facilities like buying personalized postage stamps with a personal photograph, buying newly issued postage stamps at philatelic centers, special schemes for philatelists are available at ‘post-shops’ opened at 80 post offices.
• Special limited issues of artistic postal stamps are published by the postal department in order to fulfill the requirement of philatelists.
• In this way, the service of speed post changed the very nature of the Indian postal service.

5. Answer the following questions in detail.

Question 1.
Explain India’s progress in the field of science and technology.
Answer:

• A supercomputer named ‘Param-8000’ was created with the help of C-DAC (Centre for Development of Advanced Computing, Pune. In 1998, an advanced version of ‘Param-8000’ was made which was named ‘Param-10000’.
• Its mathematical potential was enormous because of which India entered the global computer market. In 1999, India created a further version of ‘Param-10000’ which was named ‘Parampadma’. In 2003, ‘Parampadma Super Computer’ was dedicated to the nation.
• The central government’s favourable policies for the software industry, the foresightedness of Indian entrepreneurs, the nationwide spread of computer and information technology, computer engineers who are proficient in the use of the English language resulted in an increase in the Indian export of software.
• In 1995, internet services began in India. In 2004, Tata Consultancy Services was the biggest firm in Asia providing software services. Pune and Bengaluru were developed as IT hubs. Indian IT engineers are great in demand all over the world.
• In the field of science, to prove its nuclear strength, India conducted an underground nuclear test. The Indian satellite, ‘Oceansat-1’ launched and entered orbit in 1999.
• In 2000, ‘Bharat Sanchar Nigam Ltd’ (BSNL) was established to provide services like mobile phones, internet, and broadband.
• In this way, India achieved lots of progress in the field of science and technology.

Question 2.
Explain different Government schemes related to agriculture.
Answer:
According to the 2011 census, nearly 54% of India’s population is related to agriculture and agro related sector. The Government of India introduced different schemes for the progress of the agricultural sector, these schemes are as follows:

• The ‘Soil Health Card’ aims at increasing soil fertility and agricultural production.
• Pradhan Mantri Krishi Sinchan Yojana started for giving priority to water supply and irrigation facilities.
• Krishi Vikas Yojana aims at organic cultivation and increases farmer’s income.
• Pradhan Mantri Vima Yojana is implemented for the economic welfare of farmers and given the emphasis on animal husbandry, fisheries, agriculture research, and education. It also focuses on developing agriculture, co-operative establishment, and work for farmer’s welfare.
• In 2007, a national policy for farmers was adopted. If there is crop failure because of things like natural calamities, epidemics, or adverse climate, the farmers get compensated through Pradhan Mantri Peek Vima Yojana.
• Research Institute of Agricultural Sciences is supported through Indian Council for Agricultural Research. Agricultural exhibitions are organized for farmers.
• Indigenous seeds and indigenous breeds of cattle and poultry farming of indigenous variety is given priority. Goat keeping (Sheli Palan) is encouraged as an occupation.
• The ‘National Livestock Mission’ was established in 2014-15 and since then there is a rapid growth in the agricultural sector. India ranks second in fish production after China ranks first.

6. Answer the following question with the help of the given points.

Question 1.
Explain the achievement of India in the defense field.
(a) Operation Vijay
(b) Modernisation of Indian army
(c) Make in India
(d) Practice session with different countries
Answer:
(a) Operation Vijay: In 1999, Pakistan intruded Kashmir. This intrusion started a war between India and Pakistan. This war was fought in the Kargil-Drass area in Ladakh. Hence, it is known as the “Kargil War.” It is also referred to as ‘Operation Vijay’ by the Indian army. ‘Operation Vijay’ was successful and India emerged victorious in it.

(b) Modernisation of the Indian army:

• This war alerted the Indian authorities for the modernization of the Indian military. The process of updating the military, equipment, and arms, training, etc. were further intensified.
• India is the sixth country in the world to develop indigenous technology for building nuclear submarines. In 2009, India successfully built a ‘Strategic Strike Nuclear Submarine’ of the ‘Arihant class’ with the help of Russia.

(c) Make in India:

• The Government of India emphasized indigenous technology (Make in India) on recruiting women officers in the military and also on combined exercise with militaries of other countries. Women can join eight sections of the Indian army through Union Public Service Commission.
• There is an increasing focus on the exchange of the latest technology, to fight terrorism, augment our own competencies, and optimum use of modern technology for ending terrorism.

(d) Practice session with different countries: The practice session and exercise with the armies of different countries were arranged to fight terrorism. The exercise with the Oman military, Mongolian army, Sri Lankan army, and Russian army was arranged.

Question 2.
Explain the reorganization process of the states.
(a) Chhattisgarh
(b) Uttarakhand
(c) Jharkhand
(d) Telangana
(e) Jammu-Kashmir and Ladakh
Answer:
In 2000, new states were formed for the first time in India after the formation of lingual states in India.
(a) Chhattisgarh:

• Indian National Congress first put forward the demand for Chhattisgarh before independence but it was rejected by Fazal Ali Commission.
• The proposal of creating a separate state of Chhattisgarh was passed in the session of the Legislative Assembly of Madhya Pradesh in 1998.
• The state of Chhattisgarh was created by the initiative of the Government of India on 1st November 2000.

(b) Uttarakhand:

• Since 1930, the people of Garhwal and Kumaon were demanding a separate state.
• This demand was supported in the 1938 session of the Indian National Congress, however, Fazal Ali Commission ruled it out.
• The people started a movement for their demand in 1957. They also formed ‘Uttarakhand Parvatiya Rajya Parishad’ in 1973.
• In 1994, the people’s movement got intensified, hence, in recognition of popular sentiments, a bill was passed by Uttar Pradesh Legislative Assembly.
• The state of Uttaranchal, later renamed Uttarakhand, was formed on 9th November 2000.

(c) Jharkhand:

• In the year 1929, the demand for the separate state of Jharkhand was staged for the first time. It got intensified after the formation of the All India Jharkhand Party in 1947.
• An appeal was presented to the President and Prime Minister in 1973. The Bihar Legislative Assembly passed the bill ‘Jharkhand Area Autonomous Council’ in 1973. (JAAC).
• A bill providing for the division of Bihar and the creation of a separate state of Jharkhand was passed in the lower house of the parliament in August 2000 and accordingly, on 15th November 2000, a separate state of Jharkhand came into existence.

(d) Telangana:

• The state of Telangana was earlier an integral part of the state of Andhra Pradesh. A movement was started by ‘Telangana Rashtriya Samiti’ for the creation of a separate Telangana.
• In 2001, the Government of India announced the decision of the separate state of Telangana.
• The Parliament approved this demand in 2014 and on 2nd June 2014, the separate state of Telangana was formed.

(e) Jammu-Kashmir and Ladakh:

• Article 370 of the Indian Constitution gave a special status to the state of Jammu and Kashmir. In 1947, Prem Nath Dogra established the ‘Jammu Praja Parishad’ party. The motto of this party changed from ‘Ek Vidhan, Ek Pradhan, Ek Nishan’ to ‘Ek Desh me Do Vidhan, Do Pradhan, Do Nishan, Nahi Chalenge, Nahi Chalenge.
• This party demanded complete accession of Jammu-Kashmir to India but the party in power, National Conference rejected the demand.
• Dr. Shyama Prasad Mukherjee supported the demand for a complete merger. Recently in August 2019, the Government of India revoked article 370.
• From 31st October 2019, the state of Jammu and Kashmir was reconstructed as two separate Union Territories of Jammu-Kashmir and Ladakh.

Balbharti Maharashtra State Board Class 12 Economics Important Questions Chapter 2 Utility Analysis Important Questions and Answers.

Maharashtra State Board 12th Economics Important Questions Chapter 2 Utility Analysis

1. [A] Choose the correct option.

Question 1.
Form Utility increases when –
(a) dress stitched from cloth.
(b) change in the format of given material.
(c) river water diverted towards farm.
(d) pot made from clay.
Options :
(1) a, b, c
(2) b, c, d
(3) a, b, d
(4) a, b, c, d
Answer:
(3) a, b, d

Question 2.
Blood donation is an example of –
(a) place utility
(b) knowledge utility
(c) service utility
(d) form utility

Options ;
(1) a, b, c
(2) b, c, d
(3) a, b, d
(4) none of these
Answer:
(4) none of these

Question 3.
With an increase in consumption of commodity, MU curve –
(a) slopes downward
(b) goes upward
(c) turns backward
(d) shows negative slope
Options :
(1) a, d,
(2) a, b, c
(3) a, b,
(4) a, c, d
Answer:
(1) a, d,

Question 4.
After a point of satiety, any additional consumption of commodity results into –
(a) negative MU
(b) diminishing TU
(c) disutility
(d) maximum TU

Options :
(1) a, b, d
(2) a, b, c
(3) a, c, d
(4) None of these
Answer:
(2) a, b, c

Question 5.
Want satisfying power of a commodity is called –
(a) usefulness
(b) satisfaction
(c) happiness
(d) utility

Options :
(1) a, b
(2) b, d
(3) d
(4) a, c
Answer:
(3) d

Question 6.
Zero MU is described as
(a) disutility
(b) point of satiety
(c) dis-satisfaction
(d) maximum TU
Options :
(1) a, b
(2) b, d
(3) b, c, d
(4) a, b, c, d
Answer:
(2) b, d

(B) Complete the Correlation

(1) Fan in summer : Time utility :: Sweater in Shimla : …………..
(2) Additional Utility : Marginal utility :: Aggregate utility : …………..
(3) Maximum TU : Zero MU :: TU declines : …………..
(4) Measuring in numbers : …………..:: Higher or Lower level: Ordinal measurement
(5) Point of satiety : ………….. :: Beyond point of satiety: Dissatisfaction
(6) Transport of goods : ………….. :: Storage of goods : Time utility
(7) Want satisfying power : ………….. :: Use value of a commodity : Usefulness
(8) Homogeneity : Assumption of the law of DMU :: Hobbies : …………..
(9) Increases at a diminishing rate : Total Utility :: Goes on diminishing : …………..
(10) Consumer : To obtain maximum satisfaction :: …………..: To frame various economic policies
Answers:
(1) Place Utility
(2) Total Utility
(3) Negative MU
(4) Cardinal measurement
(5) Full satisfaction
(6) Place utility
(7) Utility
(8) Exception of law of DMU
(9) Marginal Utility
(10) Government

(C) Give economic terms.

(1) Want satisfying capacity of a commodity.
(2) Treatment given by a doctor to a patient.
(3) Goods sold by shopkeeper to consumer.
(4) Addition made to TU by consuming one more unit of a commodity.
(5) Aggregate of utilities derived from all units.
(6) Marginal utility becomes negative beyond the point of satiety.
(7) Utility created due to change in the structure of given material.
(8) A state of mind to feel happy.
(9) A feeling of lack of satisfaction.
(10) The urgency to satisfy want immediately.
Answer:
(1) Utility
(2) Service Utility
(3) Possession Utility
(4) Marginal Utility
(5) Total Utility
(6) Disutility
(7) Form Utility
(8) Satisfaction
(9) Want
(10) Intensity

(D) Find the odd word out:

(1) Form Utility, Time Utility, Date Utility, Place Utility.
(2) Rationality, Continuity, Reasonability, Indivisibility.
(3) Sum, Aggregate, Total, Additional.
(4) Disutility, Negative utility. Maximum TU, Declining TU.
(5) Diminishing, Declining, Developing, ; Decreasing.
(6) Miser, Drunkard, Power, Rational consumer.
Answer:
(1) Date utility
(2) Indivisibility
(3) Additional
(4) Maximum TU
(5) Developing
(6) Rational consumer

(E) Complete the following statements.

Question 1.
Utility depends upon ………………..
(a) intensity of want
(b) income of a consumer
(c) quality of a product
(d) cardinal measurement
Answer:
(a) intensity of want

Question 2.
When TU declines, MU ……………………………..
(a) is zero
(b) increases
(c) remains constant
(d) becomes negative
Answer:
(d) becomes negative

Question 3.
Consumer’s equilibrium is attained when
(a) MUX > Px
(b) MUX = Px
(c) MUX < Px
(d) MUX = zero
Answer:
(b) MUX = Px

Question 4.
Electricity can be used in Fan, TV, iron, computer, etc. because utility is ……………
(a) subjective concept
(b) multi-purpose
(c) basis of demand
(d) morally colourless
Answer:
(b) multi-purpose

Question 5.
The sum of all marginal utilities from the consumption of a commodity is called ………………
(a) place utility
(b) additional utility
(c) total utility
(d) time utility
Answer:
(c) total utility

[F] Choose the wrong pair :

I.

Group ‘A’	Group ‘B’
1. Prof. Marshall	Law of DMU
2. Total utility	Utility from last unit
3. Cardinal measurement	Assumption of law of DMU
4. Service utility	Knowledge by teacher

Answer:
Wrong pair : Total utility – Utility from last unit

II.

Group ‘A’	Group ‘B’
1. Disutilit	Negative MU
2. Homogeneity	Identical unit
3. Law of DMU	Explained by Prof. Gossen
4. Maximum TU	Zero MU

Answer:
Wrong pair : Law of DMU
Explained by Prof. Gossen

[G] Choose the correct pair :

I.

Group ‘A’	Group ‘B’
1. Total utility	(a) Point of Satiety
2. Zero MU	(b) Furniture from wood
3. Time utility	(c) Aggregate of utilities
4. Form utility	(d) Apples for Kashmir
	(e) Organ donation

Options :
(1) 1 – a, 2 – c, 3 – e, 4 – b.
(2) 1 – c, 2 – e, 3 – d, 4 – b.
(3) 1 – c, 2 – a, 3 – e, 4 – b.
(4) 1 – e, 2 – a, 3 – c, 4 – d.
Answer:
(3) 1 – c, 2 – a, 3 – e, 4 – b.

II.

Group ‘A’	Group ‘B’
1. Ordinal measurement	(a)Maximum TU
2. Principles of Economics	(b) MUX>PX
3. Point of satiety	(c) Prof. Alfred Marshall
4. Consumer’s equilibrium	(d) Grading of utility
	(e) MUX = PX

Options :
(1) 1 – d, 2 – c, 3 – a, 4 – e.
(2) 1 – c, 2 – a, 3 – b, 4 – b.
(3) 1 – d, 2 – a, 3 – b, 4 – c.
(4) 1 – b, 2 – e, 3 – d, 4 – c.
Answer:
(1) 1 – d, 2 – c, 3 – a, 4 – e.

2.[A] Identify and explain the concept from given illustrations.

Question 1.
Tanvi took umbrella while going out as it started raining.
Concept: Time utility.
Explanation : When Utility of a commodity increases during particular time period, it is called time utility.
Tanvi is using umbrella, when it is raining Ans. so, it is an example of time utility.

Question 2.
A goldsmith made a beautiful golden necklace.
Answer:
Concept: Form utility.
Explanation : When utility is created due to change in the form of given material it is known as form utility.
So, furniture from wood, dress from cloth, jewellery from gold, etc. are examples of form utility.
Thus, necklace made from gold is an example of form utility.

Question 3.
Deepak purchased bricks and transported to Thane at his construction site.
Answer:
Concept : Place utility.
Explanation : When utility arises due to change in the place of its utilisation, it is called place utility.
Transport of goods creates place utility. In this example, bricks are transported from place of production to place of utilization. So it is an example of place utility.

Question 4.
Mugdha bought raw mangoes and made pickle from it.
Answer:
Concept: Form utility.
Explanation : When utility increases due to change in the shape, structure or form of material, it is called form utility. So, pickle made from raw mangoes, is an example of form utility.

Question 5.
Aditi went to Beauty Parlour to cut her hairs.
Answer:
Concept: Service utility.
Explanation : When service is provided by one person to another, it is called service utility.
It includes services rendered by professionals like doctors, lawyers, teachers, etc.
In this case, a beautician has given service to Aditi.
So, it is an example of service utility.

(B) Distinguish between

Question 1.
Utility and Usefulness.
Answer:

Utility	Usefulness
1. Utility is the capacity of a commodity to satisfy human wants.	(a) Anything (goods or services) are useful if they satisfy human want and generate human welfare.
2. A product may have utility irrespective of the commodity is useful or harmful, desirable or undesirable.	(b) A product is useful only when it is desirable or beneficial and does not do any harm to a person.
3. All commodities have utility such as car, clothes, even harmful products like drugs, liquor, cigarettes, narcotics, etc.	(c) Products such as food items, medicine, clothes, etc. are useful. Also services such as education, recreation are useful to people.
4. The term utility is subjective in nature as it changes from person to person, from place to place and from time to time.	(d) The term usefulness is absolute in nature, it never changes.

Question 2.
Utility and satisfaction.
Answer:

Utility	Satisfaction
1. Utility is a want satisfying capacity possessed by a commodity.	(a) Satisfaction is actual realisation from consumption of a commodity.
2. It is what the commodity possesses.	(b) It is what the commodity gives.
3. It is a means.	(c) It is an end.
4. It is expected satisfaction before consumption.	(d) It is actual realisation which comes after consumption.

Question 3.
Place Utility and Time Utility.
Answer:

Place Utility	Time Utility
1. Place utility is created by changing the place of utilisation.	(a) Time utility is created by changing the time of utilisation.
2. Transporting goods from one place to another, generally from place of abundance to place of scarcity, from place of manufacturing to place of consumption (Market), etc.	(b) Storing of goods during abundance and releasing them during scarcity or goods are warehoused from time of production to time of consumption.
3. All types of transport service create place utility.	(c) Warehousing service create time utility.
4. E.g. Food grains from village farm are sold in city markets.	(d) E.g. Wheat stored during harvest time and released during off season.

Question 4.
Total Utility and Marginal Utility.
Answer:
Total Utility :

1. Total utility is the sum total of utilities derived from the consumption of all units in a given stock of a commodity.
2. TU =Σ MU
3. TU increases but at a diminishing rate.
4. At point of satiety TU is maximum.
5. After point of satiety TU starts diminishing.
6. Numerical value of TU is always positive.
7. TU indicates value-in-use.
8. When TU is maximum, the MU is zero.

Marginal Utility :

1. Marginal utility is the additional utility derived from consuming additional unit of a commodity.
2. MU_n = TU_n – TU_n-1
3. MU continuously diminishes.
4. At point of satiety MU is zero.
5. After point of satiety MU becomes negative.
6. Numerical value of MU can be positive, negative or zero.
7. MU indicates value-in-exchange.
8. When the MU is maximum the TU is minimum.

Question 5.
Form Utility and Service Utiliity.
Answer:
Form Utility :

1. Form utility arises when the structure of given material changes.
2. Furniture made out of wood is an example of form utility.
3. It is related to material welfare.
4. Form utility is mainly created by artisans like tailor, carpenter, etc.

Service Utility :

1. It arises when service is rendered by one person to another.
2. Knowledge given by teacher to student is an example of service utility.
3. It is related to non-material welfare.
4. Service utility is mainly created by professionals like doctor, lawyers, etc.

Question 6.
Knowledge Utility and Possession Utility.
Answer:
Knowledge Utility:

1. Knowledge utility arises when a person acquires knowledge regarding a product.
2. Use of mobile, computer, etc. creates knowledge utility.
3. In this case, a consumer is interested to know various functions of product.
4. Knowledge utility increases due to utilisation.

Possession Utility:

1. Possession utility arises when the ownership of a product is transferred from one person to another.
2. Sale and purchase of goods creates possession utility.
3. In this case, a consumer is interested to satisfy his wants.
4. Possession utility increases due to demand.

Question 7.
Form Utility and Time Utility.
Answer:
Form Utility :

1. Form utility arises when the structure of given material changes.
2. E.g. Furniture made out of wood.
3. Technology and intelligence creates form utility.

Time Utility:

1. Time utility is created by changing the time of utilisation.
2. E.g. Wheat stored during harvest season and released during off season.
3. Warehousing creates time utility.

3. Answer the following questions:

Question 1.
Critically evaluate the law of Diminishing Marginal Utility.
OR
Explain the limitations or shorcomings of law of DMU.
Answer:
Critical evaluation of the Law of DMU is as follows:
(1) Unrealistic Assumptions : The law of DMU is based upon some unrealistic assumptions like homogeneity, continuity, rationality, constancy, etc.
In reality, it is very difficult to fulfil all these ssumptions at a time.

(2) Cardinal Measurement – not possible : The law assumes that, utility is cardinally measurable. It is necessary for the law to express schedule indicating MU and TU. It helps to add, subtract and compare utilities, In the real sense, utility is a psychological concept so it cannot be measured cardinally i.e. in numbers.

(3) Not applicable to Indivisible Goods : The law assumes divisibility. So it is not applicable to indivisible or bulky goods like car, T.V. set, house, etc. which are not divisible.
It is not possible to compare MU from commodity which are normally purchased, once in a life time.

(4) Constant MU of Money: The law assumes that MU of each unit of money is constant. But, in reality, MU of money declines as its stock increases.
Critics also argue that MU of money differs from person to person. It is affected by changes in price level, stock of money, rate of interest, etc.

(5) Restricted to satisfaction of Single Want : The law of DMU has limited applicability. It analyses the satisfaction derived from single want.
In reality, human wants are multiple in nature i.e. a person has to satisfy many wants at a time.
Though, law of DMU is criticized, it is important and popular in economics, because it explains economics behavior of a rational consumer.

Question 2.
Explain the significance importance of Law of Diminishing Marginal Utility.
Answer:
The law of DMU has universal applicability so it is an important law in economics.
Importance or significance of the law of DMU is as follows :

(1) Useful to Consumers : The law is important to the consumer because it helps the consumer to maximize his satisfaction.
It creates awareness among the consumers 5 to get maximum satisfaction with limited resources.

(2) Useful to the Government : The law ; guides the government in framing various economics policies like progressive tax policy, pricing policy, trade policy, import export policy, etc. so as to maximise
economic welfare of the society.

(3) To understand Paradox of Value : The law of DMU helps us to understand paradox of values, i.e. value-in-use and value-in-exchange.

Some goods have more value-in-use but less value-in-exchange like air, water, sunlight, etc. while some goods have less value-in-use but high value-in-exchange like gold, diamond, etc. Greater value-in-use denotes high total utility whereas, more value in exchange denotes higher marginal utility.

(4) Basis of Law of Demand : The law of demand is based on the law of DMU.
A consumer compares MU with price of a commodity. He purchases till MU equals price. When a consumer buys more and more units of a commodity, his MU diminishes. It means, a consumer would buy more only at a lower price which is a basis of law of demand.

Question 3.
Explain the features / characteristics of Utility.
Answer:

(1) Multi-purpose : Utility is said to be multi-purpose because a commodity can be used to satisfy several wants. It can satisfy wants of more than one person at a time.
E.g. milk has multi-purpose utility. It can be used to make coffee, ice- cream, milk-shake, tea, etc.
Similarly, in case of commodities like coal, electricity, etc. utility is multi-purpose.

(2) Relative Concept : Utility is a relativeconcept because it is related to time, place and person. It changes from time to time, place to place and from person to person.
E.g. fan has greater utility in summer than
winter, sweater has greater utility in cold regions.

(3) S ubjective Concept: Utility is a subjective term. It varies from person to person. It differs on the basis of taste and preferences, habits, likes, dislikes, profession, situation, etc. e.g. chalk has utility for teachers and not for doctors. Fish has utility for non¬vegetarian person etc.

(4) Basis of Demand : A person will demand only those commodities which give him utility. No utility means no demand, so utility is the basis of demand.
E.g. a student demands a book because he has utility of a book. Thus, utility creates demand for a product.

(5) Intensity of Want: Utility of a commodity is greater if a want is most urgent, whereas, utility is less if the intensity of want is less. Utility diminishes when the urgency of want declines. E.g. a thirsty person gets more utility from the first sip of water than the next one.

(6) Measurement of Utility : Utility is a psychological concept. So utility cannot be measured cardinally, that is, in numbers. Ordinal measurement, i.e. higher or lower level of utility can be measured.
E.g. a hungry person may experience higher or lower utility after having food. However, X it is assumed that cardinal measurement of i utility is possible, for the validity of the law 5 of diminishing marginal utility.

(7) Utility is morally Colourless : Utility is ethically neutral concept. It has no moral consideration. It is morally colourless. It does not consider whether a want is good or bad, moral or immoral, desirable or undesirable. A commodity can be used to satisfy any kind of want. It can be useful or harmful.
E.g. a knife can be used to cut vegetables, as well as, it can be also used to harm somebody. Thus, utility does not have ? ethical consideration.

(8) Utility differs from Usefulness : Utility and usefulness are different concepts. Utility means want satisfying capacity of a commodity whereas usefulness means use value of a commodity.
Some commodities have both, utility and usefulness. E.g. watch, pen, etc.
However, some commodities have utility but no usefulness.
e.g. cigarette has utility for those who smoke but it is not at all useful as it has an adverse effect on human health.

(9) Utility differs from Pleasure : There is a difference between utility and pleasure, Certain commodities which possess utility, may not give pleasure.
E.g. a course of injections given to patient, has utility because it cures him however, it may not give pleasure or happiness as it is a painful experience.

(10) Utility differs from Satisfaction : Utility and satisfaction, interrelated concepts but, utility is not same as satisfaction. Utility refers to power of a good to a satisfy human want. Satisfaction is a state of mind to feel happy.
Utility arises before the consumption of a commodity. However, satisfaction is received after the consumption of a commodity. It is because, utility is anticipated satisfaction, whereas, satisfaction is actual realisation.
Utility is related to commodity but satisfaction is experienced by a person.

Question 4.
What are the different types or forms of utility?
Answer:
Types of utility :

1. Form utility
2. Place utility
3. Service utility
4. Knowledge utility
5. Possession utility
6. Time utility

Types of utility are explained as under:

(1) Form utility : It arises due to a change in the shape of an object. When utility is created because of change in the structure or form of a given material, it is known as form utility.
E.g. furniture made of wood, dress from cloth, jewellery from gold, etc.

(2) Place utility : Utility changes from place to place. When utility arises due to change in the place of its utilisation, it is called as place utility. Transport of goods and services creates place utility.
E.g. utility of river water increases when it is diverted towards farm.
Shawls have greater utility in cold regions than any other place.

(3) Service utility : When service is provided by professionals to another person, it creates service utility. It includes services rendered by Doctor to patient, Lawyer to client, Teacher to student, etc.

(4) Knowledge utility : In this case, utility increases when a person acquires knowledge regarding specific product.
For example, when a consumer knows about various functions of a laptop, its utility increases, Similarly, use of mobile, computer, sewing machine etc. creates knowledge utility.

(5) Possession utility : It is related to the ownership of goods. When the ownership of a product is transferred from one person to another, it creates possession utility.
E.g. transfer of ownership of food grains from farmer to consumer.
Thus, possession utility arises when goods are transferred from sellers to buyers.

(6) Time utility : When utility of a commodity changes due to change in time period, it is called time utility.
E.g. an umbrella has greater time utility during rainy season.
Time utility also takes place when goods are stored and used as per the requirement. Time utility varies from season to season or from situation to situation.
So, blood donation creates time utility.

4. State with reasons whether you agree or disagree with the following statements:

Question 1.
Utility is a subjective concept.
Answer:
Yes, I agree with this statement.
It is a psychological concept. It is the mental assessment of a commodity. So utility differs from person to person because of difference in taste, preference, likes and dislikes of a person e.g., Chalks have more utility to a teacher than a student.

Question 2.
Utility and happiness are different.
Answer:
Yes, I agree with this statement.

• Utility is want satisfying capacity of a commodity and happiness is an enjoyable experience.
• When a commodity has utility it may not necessarily give happiness or pleasure or enjoyable experience to consumer. E.g., no one enjoys taking an injection or bitter medicine but they have utility to a patient.

Question 3.
Utility is ethically neutral.
OR
The concept of utility has no moral or ethical consideration. (Feb. ‘16)
Answer:
Yes, I agree with this statement.

• Utility is morally colourless concept.
• As long as a commodity possesses the want satisfying power, it has utility for a person irrespective of the fact that the commodity is good or bad, desirable or undesirable, moral or immoral.
• e.g., Knife has the utility for both a killer (for stabbing) and a housewife (as kitchen appliance).
• Similarly liquor has utility to a drunkard but from ethical point of view their consumption may be undesirable .

Question 4.
Utility means not usefulness.
Answer:
Yes, I agree with this statement.
Utility indicates the power of a good to satisfy human wants irrespective of whether it is good or bad or harmful. Whereas usefulness means that the commodity is beneficial or desirable. A commodity may have utility but may not be useful e.g., Cigarette is injurious to health. It is not useful but it has utility to a smoker.

Question 5.
Utility is a psychological term.
Answer:
Yes, I agree with this statement.

• Utility relates to consumer’s mental attitude and experience regarding a given commodity.
• So utility differs from person to person.
• The utility of a good cannot be the same for all individuals.
• This is due to difference in taste, preference, likes and dislikes.
• E.g. fish has utility to non-vegetarian but not to a pure vegetarian.

Question 6.
Utility depends on urgency of want Or Utility depends upon intensity of want.
Answer:
Yes, I agree with this statement.

• Utility for a commodity is dependent on the intensity of need for that commodity.
• If a want is very intense or urgent for the commodity concerned then he will find more utility from the commodity.
• As the intensity of want falls, its utility diminishes. For example first slice of bread will give more utility to a hungry person than the 2nd or 3rd slice of bread. Books have more utility to students just before exams and no utility after the exams.

Question 7.
Utility of same commodity for two c persons is different.
Answer:
Yes, I agree with this statement.

• Utility is affected by personal likes, dislikes, preference, habits, etc.
• Utility changes from person to person. It is subjective concept.
• It is psychological feeling and subject to change from person to person.
• E.g. Cigarette has utility to a smoker but it has no utility to non-smoker.
• Marginal Utility diminishes.

Question 8.
Marginal Utility diminishes.
Answer:
Yes, I agree with this statement.

• Marginal utility diminishes with increase in consumption of a commodity.
• When the stock of the commodity increases the intensity of want decreases so the utility diminishes.
• There is an inverse relation between the stock of commodity and.MU.
• The law of DMU states “The additional benefit which a person derives from a given increase in the stock of a
• thing, diminishes with every increase in the stock that he already has.

Question 9.
Utility can be measured cardinally.
Answer:
No, I do not agree with this statement.

• Utility being a psychological concept it cannot be quantified in numbers such as 10, 20, 30 so on.
• It is a feeling so can be only be expressed ordinally.
• It can be expressed as 1st, 2nd, 3rd and so on, in order of preference or can be graded.
  It is intangible.
  But Marshall has assumed that utility can be measured in cardinal numbers to explain the law of Diminishing Marginal Utility but different concepts.

Question 10.
Utility and satisfaction are different concepts.
Answer:
Yes, I agree with this statement.

• Utility is the quality possessed by the commodity before consumption of the goods. It is expected satisfaction.
• Satisfaction is actual realisation, which is derived after the consumption.
• Utility is the means and satisfaction is the end result of consumption.
• Utility is what commodity possesses whereas satisfaction is what we experience after consumption.
• Utility and satisfaction are synonyms but different concepts.

Question 11.
It is more appropriate to tax the rich in excess than the poor.
Answer:
Yes, I agree with this statement.

• The law of diminishing marginal utility supports the progressive tax system.
• The rich are taxed more because they can easily bear the burden of heavy tax as they have more stock of money. Therefore, they find less MU in money.
• The poor have less stock of money. Therefore, they find more MU in money. So they are taxed less.
• In this way the Government follows the “Principle of Equity” while taxing the people.
• Also indirect tax on mass consumption goods or necessaries are less compared to the luxury goods.

Question 12.
The hobby of stamp collection is not a real exception to the law of Diminishing Marginal Utility.
Answer:
Yes, I agree with this statement.

• It is wrongly believed that the hobby of stamp collection is an exception to the law of DMU.
• It is observed that every successive stamp collected gives more MU to the person.
• But in reality a person collects different types of stamps. Thus it violates the assumption of homogeneity and continuity.
• If a person is asked to collect the same type of stamp again and again the MU will= diminish. Therefore, the hobby of stamp collection is not a real exception to law of DMU. It is an apparent exception.

Question 13.
There are no real exceptions to the law of DMU.
Answer:
Yes, I agree with this statement.
[Note : For answer refer Q.6. (1) (D)
Schedule and Diagram :
The law can be explained with the help of following schedule and diagram :

Units of Commodity	Marginal Utility (M.U)
1	10
2	8
3	6
4	4
5	2
6	0
7	-2

The above given schedule shows that MU goes on diminishing with an increases in units of commodity consumed.
Graphical Presentation :

In the above given diagram, X-axis indicates units of commodity and Y-axis measures marginal utility.
Various points are plotted on the graph which indicates MU derived from each unit of commodity consumed.
When all these point are joined, we get MU curve. It slopes downward from left to right. It shows that MU diminishes as consumption of a commodity increases.
The shaded portion of the diagram shows negative utility. It is because, beyond a certain level, further consumption of a commodity results into disutility.

Question 14.
Law of DMU is important in practice.
Answer:
Yes, I agree with this statement.
The law of DMU has universal applicability so it is an important law in economics. Importance or significance of the law of DMU is as follows :

(1) Useful to Consumers : The law is important to the consumer because it helps the consumer to maximize his satisfaction.
It creates awareness among the consumers 5 to get maximum satisfaction with limited resources.

(2) Useful to the Government : The law ; guides the government in framing various economics policies like progressive tax policy, pricing policy, trade policy, import export policy, etc. so as to maximise
economic welfare of the society.

(3) To understand Paradox of Value : The law of DMU helps us to understand paradox of values, i.e. value-in-use and value-in-exchange.
Some goods have more value-in-use but less value-in-exchange like air, water, sunlight, etc. while some goods have less value-in-use but high value-in-exchange like gold, diamond, etc. Greater value-in-use denotes high total utility whereas, more value in exchange denotes higher marginal utility.

(4) Basis of Law of Demand : The law of demand is based on the law of DMU.
A consumer compares MU with price of a commodity. He purchases till MU equals price. When a consumer buys more and more units of a commodity, his MU diminishes. It means, a consumer would buy more only at a lower price which is a basis of law of demand.

Question 15.
(i) When the MU is zero, TU is maximum.
Answer:
Yes, I agree with this statement.
OR
(ii) When MU is zero, TU diminishes.
Answer:
No, I do not agree with this statement.

• When MU is zero the TU is the maximum.
• MU is the additional utility derived from the consumption of last unit of commodity.
• The TU is the sum of utilities derived from all units of consumption.
• The inter relationship between MU and TU can be explained with the help of the schedule.
  

  Units of Commodity	Marginal Utility (M.U)
  1	10
  2	8
  3	6
  4	4
  5	2
  6	0
  7	-2

• From the schedule it can be observed that when a consumer keeps on consuming the same commodity continuously the MU diminishes and TU increases but at a diminishing rate.
• At the point of satiety i.e., unit 5 the consumer enjoys maximum satisfaction. Therefore, the MU becomes zero and TU reaches maximum i.e., 28 units.
• Here the consumer is fully satisfied. If the consumer keeps on consuming further units of the commodity after satiety, he derives dissatisfactions. Therefore, the MU becomes Negative and TU also starts falling or decreasing.
• Thus, at the point of full satisfaction MU is zero and it intersects the ‘X’ – axis and TU is maximum

Question 16.
The law of DMU could be explained type of stamp again and again the MU will with example and diagram.
OR The law of DMU can be explained with schedule and graph.
Answer:
Yes, I agree with this statement.
Schedule and Diagram :
The law can be explained with the help of following schedule and diagram :

Units of Commodity	Marginal Utility (M.U)
1	10
2	8
3	6
4	4
5	2
6	0
7	-2

The above given schedule shows that MU goes on diminishing with an increases in units of commodity consumed.
Graphical Presentation :

In the above given diagram, X-axis indicates units of commodity and Y-axis measures marginal utility.
Various points are plotted on the graph which indicates MU derived from each unit of commodity consumed.
When all these point are joined, we get MU curve. It slopes downward from left to right. It shows that MU diminishes as consumption of a commodity increases.
The shaded portion of the diagram shows negative utility. It is because, beyond a certain level, further consumption of a commodity results into disutility.

Question 17.
The diminishing Marginal Utility Curve goes upwards means it has a positive slope
Answer:
No, I do not agree with this statement.
(a) The MU curve slopes downwards from left to right and it has a negative slope as shown in the diagram.

(b) The MU curve has a negative slope which indicates inverse relationship between the stock of the commodity and MU.
(c) The law states that the additional benefit which a person derives from a given increase in his stock of a thing diminishes with every increase in the stock that he already has.
(d) It means that the MU goes on diminishing with an increase in the stock of commodity consumed.
(e) It means that the intensity of want decreases.
(f) With increase in stock of commodity, the satisfaction derived decreases, so it has a negative slope.

Question 18.
The law of DMU depends upon assumptions.
Answer:
Yes, I agree with this statement.
OR
Homogeneity is the only assumption to law of DMU.
Answer:
No, I do not agree with this statement.

Assumptions of the law of DMU :
Assumptions are those conditions which are necessary for the validity of the law. They are as follows :

• Cardinal Measurement: The law assumes that utility can be measured cardinally i.e. in numbers. So, it is possible to express and compare the utility derived from each unit of commodity consumed.
• Homogeneity : It is assumed that all the units of commodity consumed are homogeneous or same. They are identical in case of size, shape, taste, colour, flavor, etc.
• Rationality : A consumer is assumed to be rational. His behaviour is normal from economic’s point of view. It means, he tries to get maximum satisfaction.
• Continuity : All units of commodity are consumed successively, one after another, without time interval.
• Reasonability : The law assumes that, all the units of commodity consumed are reasonable in size. The unit of measurement is neither too big nor too small e.g. a cup of tea, glass of water, etc.
• Divisibility : A commodity is assumed to be divisible. So it is possible to divide the units of commodity in a proper size.
• Constancy : It is assumed that related factors like income, taste and preference, habits, choice of a consumer remain constant. MU of money is also assumed to be constant.
• Single want: A given commodity is used to satisfy a single want of a person. So that it is possible to experience full satisfaction from a single want.

Question 19.
Marginal Utility and Total Utility are same.
Answer:
No, I do not agree with this statement.
MU and TU are different.
Total Utility :

1. Total utility is the sum total of utilities derived from the consumption of all units in a given stock of a commodity.
2. TU =Σ MU
3. TU increases but at a diminishing rate.
4. At point of satiety TU is maximum.
5. After point of satiety TU starts diminishing.
6. Numerical value of TU is always positive.
7. TU indicates value-in-use.
8. When TU is maximum, the MU is zero.

Marginal Utility :

1. Marginal utility is the additional utility derived from consuming additional unit of a commodity.
2. MU_n = TU_n – TU_n-1
3. MU continuously diminishes.
4. At point of satiety MU is zero.
5. After point of satiety MU becomes negative.
6. Numerical value of MU can be positive, negative or zero.
7. MU indicates value-in-exchange.
8. When the MU is maximum the TU is minimum.
   

Question 20.
There are no criticisms to the law of DMU.
Answer:
No, I do not agree with this statement.
Answer:
There are many criticisms / limitations.
Critical evaluation of the Law of DMU is as follows:

• Unrealistic Assumptions : The law of DMU is based upon some unrealistic assumptions like homogeneity, continuity, rationality, constancy, etc.
  In reality, it is very difficult to fulfil all these assumptions at a time.
• Cardinal Measurement – not possible : The law assumes that utility is cardinally measurable. It is necessary for the law to express schedule indicating MU and TU. It helps to add, subtract and compare utilities, concept so it cannot be measured cardinally i.e. in numbers.
• Not applicable to Indivisible Goods : The law assumes divisibility. So it is not applicable to indivisible or bulky goods like car, T.V. set, house, etc. which are not divisible.
  It is not possible to compare MU from commodity which are normally purchased, once in a life time.
• Constant MU of Money: The law assumes that MU of each unit of money is constant. But, in reality, MU of money declines as its stock increases.
  Critics also argue that MU of money differs from person to person. It is affected by changes in price level, stock of money, rate of interest, etc.
• Restricted to satisfaction of Single Want The law of DMU has limited applicability. It analyses the satisfaction derived from single want.

In reality, human wants are multiple in nature i.e. a person has to satisfy many wants at a time.
Though, law of DMU is criticized, it is important and popular in economics, because it explains economics behavior of a rational consumer.

Question 21.
Utility is a relative concept.
Answer:
Yes, I agree with this statement.
Relative Concept : Utility is a relative concept because it is related to time, place and person. It changes from time to time, place to place and from person to person.
E.g. fan has greater utility in summer than winter, sweater has greater utility in cold regions.

5. Study the following table / figures / passages and answer the questions :

Question 1.
Observe the given table and answer the questions:

Units of Com. ‘X’	MU	TU
1	12	12
2	8	20
3	5	25
4	3	28
5	0	28
6	-2	26

(1) Draw MU and TU curve with the help of given schedule.
Answer:

(2) What is TU at zero MU?
Answer:
T.U. is maximum, at zero MU.

(3) Complete the sentence :
With an increase in consumption, MU goes on diminishing and TU …..
Answer:
With an increase in consumption, MU goes on diminishing and TU goes on increasing at a diminishing rate.

(4) What happens to MU when TU falls?
Answer:
MU becomes negative when TU falls.

Question 2.
Observe the given table and answer the questions:

Units of Com. ‘X’	TU Units	MU Units
1	6	6
2	11	5
3	15	4
4	15	0
5	14	-1

(1) Draw TU and MU curve.
Answer:

(2) Fill in the blanks :
(a) When total utility is maximum marginal utility is ……………..
Answer:
When total utility is maximum marginal utility is zero.

(b) When total utility falls, marginal utility becomes ……..
Answer:
When total utility falls, marginal utility becomes negative.

6. Answer in detail:

Question 1.
Explain the relationship between MU and Price.
Answer:
The relationship between MU & Price helps to understand, how the law of DMU forms ’ the basis of law of demand.
It is a perfect example of application of law of DMU practically. In this case, MU is converted in terms of money to understand this relationship and the comparison between MU & price.

Let us assume that 1 unit of MU = ₹ 10/- Market price per unit of commodity x = ₹ 50/- The table given below, explains the relationship between MU and price. It helps to know consumers equilibrium.

The above given table indicates that a consumer purchase units of commodity ‘x’ one after another. 2nd column shows MU derived from each unit. It goes on diminishing with every unit of commodity consumed.
To compare MU with price, it is necessary to ) convert MU in terms of money.
Let us assume that, 1 unit of MU = ₹ 10/- So, units of MU multiplied by ₹ 10/- (as shown in column

Market price of each unit of commodity ‘x’ is ₹ 50/- (as shown in column 4)
Column 5 shows comparison between MU and price.
It is observed that, for the first and second unit, MU (in terms of money) is greater than the price paid for them it means MU_x > P_x.

So, a rational consumer will be willing to buy 1st and 2nd unit of commodity ‘x’.
At the 3rd unit a commodity ‘x’ MU equals ) the price. So, the consumer can also think of purchasing it. Here, MU_x = P_x.
But, in case of 4th and 5th unit, MU is less than price. Therefore, a rational consumer will not purchase these units because MU_x < P_x

The relationship between MU and price can be summarised as follows :

1. When MU is greater than price, a consumer is willing to buy those units. They are called Intra- Marginal units (MU_x > P_x).

2. When MU becomes equal to market price, a consumer can also think of buying that unit. It is called Marginal unit (MU_x = P_x = Consumer’s equilibrium).

3. When MU is less than price, a rational consumer is not willing to buy them. They are called Extra-marginal units (MU_x < P_x) Thus, a rational consumer attains equilibrium where MU_x = P_x.
The relationship between MU and price helps to understand the law of demand.

Question 2.
Explain the various concepts of Utility.
Answer:
There are two main concepts of utility :
Marginal Utility (MU)
Total Utility (TU)
They are explained as follows :

1. Marginal Utility (MU) : MU refers to the additional utility derived by a consumer from the last unit of a commodity consumed. In simple words, MU is the addition made by one more unit of a commodity consumed.

2. Total Utility (TU) : TU means the sum of utilities derived by a consumer from all units of commodity consumed.
It is an aggregate of utilities derived from all units.
Symbolically, it can be represented as follows :
MU = Marginal Utility
TU Total Utility
MU₁, MU₂ , MU₃, = Marginal Utilities
derived from each unit.
MU_n = Marginal utility of nth unit.
MU_n = TU_n -TU(_n-1)
TU_n = Total utility of nth unit.

TU(_n-1) = Total utility of nth previous unit.
TU_n = ΣMU_n or
TU_n = MU₁ + MU₂ + …………………. +MU_n
TU of nth unit = Summation of marginal utilities up to nth unit.

Question 3.
Explain the relationship between MU and TU.
Answer:
MU & TU are inter-related concepts but there is a difference between MU and TU because MU shows utility derived from each unit whereas, TU indicates summations of marginal utilities.
It can be explained with the help of following schedule –

The above given schedule indicates MU derived from each successive unit & TU – summation of MU’s.
On the basis of given schedule, MU curve and TU curve can be drawn, as shown in the following diagram.

In the given diagram X’ axis indicates units of commodity and ‘Y’ axis measures TU & MU.
MU curve slopes downward whereas; TU curve goes upward.
MU curve shows zero and negative level of satisfaction whereas, TU curve shows maximum level of satisfaction.
The relationship between MU and TU can be summarized as follows:

1. When the 1st unit of commodity is consumed, MU is equal to TU. (MU = TU)
2. From 2nd consumption, MU goes on diminishing and TU increases at a diminishing rate. (MU↓↓↓. and TU ↑↑↑)
3. At a full satisfaction level, MU becomes zero & TU reaches at maximum level. It becomes constant. It is called point of satiety. (MU zero, TU max^m)
4. After a point of satiety, any additional consumption of unit results into negative MU while TU starts declining.
   (MU —ve, TU↓)
5. If any unit of commodity consumed beyond the point of satiety, consumer experiences dissatisfaction.

Balbharti Maharashtra State Board Class 12 Economics Important Questions Chapter 7 National Income Important Questions and Answers.

Maharashtra State Board 12th Economics Important Questions Chapter 7 National Income

1. A. Choose the correct option:

Question 1.
At present National Income estimation is done by …………………
(a) Central Statistical Organization
(b) Finance Department
(c) National Income Committee
(d) Reserve Bank of India
Options :
(1) a, b and c
(2) c and d
(3) a and b
(4) only a
Answer:
(4) only a

Question 2.
National Income is the subject matter of ……………… economics.
(a) Micro
(b) Marco
(c) Managerial
(d) Business
Options:
(1) a and b
(2) only b
(3) only c
(4) None of these
Answer:
(2) only b

Question 3.
National income is a …………… concept
(a) static
(b) final
(c) flow
(d) reserve
Answer:
(a) static

Question 4.
The members of National Income Committee in 1949 were —
(a) Prof. P.C. Mahalanobis and Prof. D.R.Gadgil
(b) Prof. P.C. Mahalanobis and Kaushik Basu
(c) Abhijit Banerjee and Amartaya Sen
(d) Prof. P.C. Mahalanobis, D. R. Gadgil and Dr. V.KR.V. Rao
Answer:
(d) Prof. P.C. Mahalanobis, D. R. Gadgil and Dr. V.KR.V. Rao

Question 5.
According to National Income Committee, NI is ………………….
(a) volume of goods and services
(b) produce in one year
(c) goods and services counted without duplication
(d) all of these
Options :
(1) a and b
(2) a and c
(3) only a
(4) d
Answer:
(4) d

Question 6.
Statements incorrect with reference to A.C. Pigou definition –
(a) National income means national dividend
(b) Objective income of the community
(c) Income from abroad does not include
(d) Income from abroad in money term
Options :
(1) b and c
(2) only a
(3) only c
(4) all of these
Answer:
(3) only c

Question 7.
While measuring National Income value of ……………….
(a) all goods and services are considered
(b) final goods and services are considered
(c) only intermediate goods are considered
(d) none of these
Options :
(1) a and c
(2) only b
(3) a and b
(4) only d
Answer:
(2) only b

Question 8.
Net income from abroad includes
(a) Difference between export value and import value (X-M)
(b) Difference between receipts and payments made abroad (R-P)
(c) Difference between value of raw material and final goods
(d) None of these
Options :
(1) a and b
(2) b and c
(3) a and c
(4) only c
Answer:
(1) a and b

Question 9.
Three sector economy consists of ……………..
(a) households, business firms and industries
(b) households, business firms and government sector
(c) households, government and foreign sector
(d) all of these
Options :
(1) only a
(2) only b
(3) only c
(4) only d
Answer:
(2) only b

Question 10.
Which of the following is included in j four sector economy?
(a) Households, firms, industries and government
(b) Household, government, firms and organisation foreign sector
Options :
(1) only a
(2) c and d
(3) only d
(4) a and
Answer:
(3) only d

Question 11.
GDP (Gross Domestic Product) =
(a) C +1 + G + (X-M)
(d) GNP – depreciation
(c) GDP – depreciation
(b) C + I + G + (R-P)
Options :
(1) a
(2) b
(3) c
(4) d
Answer:
(1) a

Question 12.
GNP = C +1 + G + (X-M) + (R-P), R and P represents …………….
(b) R – receipts from abroad
(c) P – payments made abroad
(d) P – payments to government
Options :
(1) a and c
(2) b and c
(3) c and d
(4) a and d
Answer:
(2) b and c

Question 13.
Green Gross National Product (GNP) includes –
(a) Sustainable economic development
(b) Equitable distribution of benefits
(c) Promotes economic welfare
(d) All of these
Options :
(1) a and b
(2) b and c
(3) only c
(4) only d
Answer:
(4) only d

Question 14.
Value added approach is the difference between the value of ……………….
(a) Export and import
(b) Receipts and payment
(c) Inputs and final output
(d) None of these
Options :
(1) a and b
(2) b and c
(3) only c
(4) d
Answer:
(3) only c

Question 15.
Income method of measuring national income is the sum of …………………..
(a) Rent and profit
(b) Rent + Wages + Interest + Profit + MI + (X-M)
(c) C + I + G + (X-M)
(d) Interest + Wages
Options :
(1) a and d
(2) only b
(3) c and d
(4) b and c
Answer:
(2) only b

Question 16.
Transfer income includes ………………
(a) pension and scholarships
(b) gifts and donations
(c) donations and unemployment allowance
(d) all of these
Options :
(1) a and b
(2) b and c
(3) a and c
(4) d
Answer:
(4) d

Question 17.
WThile estimating National Income by income method the following precautions should be taken –
(a) transfer income should be ignored
(b) all unpaid services should be ignored
(c) income from sale of second hand goods should be ignored
(d) undistributed profits should be ignored
Options :
(1) a and b
(2) c and d
(3) a, b and c
(4) only d
Answer:
(3) a, b and c

Question 18.
In advance countries like USA and UK the ……………….. method of measuring NI is popular.
(a) Output Method / Product Method
(b) Income Method / Factor Cost Method
(c) Expenditure Method / Outlay Method
(d) None of these
Options :
(1) a and b
(2) only b
(3) b and c
(4) d
Answer:
(2) only b

Question 19.
Mixed Income (MI) refers to the income of ………………….
(a) Private and public sector
(b) Self-employed persons
(c) Sale of second hand goods
(d) All of these
Options :
(1) a
(2) b
(3) c
(4) d
Answer:
(2) b

Question 20.
There are many theoretical difficulties in the measurement of NI like –
(a) Transfer Payment
(b) Illegal Income
(c) Unpaid services
(d) All of these
Options :
(1) a and b
(2) b and c
(3) a and c
(4) d
Answer:
(4) d

Question 21.
There are many practical difficulties in the measurement of NI like –
(a) problem of double counting
(b) existence of non-monetize sector
(c) inadequate and unreliable data
(d) none of these
Options :
(1) a and b
(2) b and c
(3) a, b and c
(4) only d
Answer:
(3) a, b and c

Question 22.
National income is extremely useful for ……………..
(a) formulating national policies on employment, industry, etc.
(b) economic planning
(c) distribution of income
(d) all of these
Options
(1) a and b
(2) b and c
(3) a and c
(4) d
Answer:
(4) d

(B) Complete the correlation

1. Personal income : Micro economics :: National Income : …………….
2. Two sector economy : Household and business firms :: ……………. : Households, Business firms, Government and Foreign sector
3. Three sector economy :Y=C + I + G:: Four sector economy : …………….
4. (X-M) : ……………. :: (R-P) : difference between receipts and payment from abroad
5. …………….: GDP – Depreciation :: NNP : GNP – Depreciation
6. GNP : C + I + G + (X-M) + (R-P) :: ……………. : GNP – (net fall in stock of natural capital + pollution load)
7. ……………. : Value of final goods and service ::
   Value added approach : Difference between value of output and input
8. Output Method : Product Method :: ……………. Outlay Method
9. ……………. : Unpaid services :: Practical difficulty : Problem of double counting

Answer:

1. Marco economics
2. Four sector economy
3. Y = C + I + G + (X-M)
4. Difference between value of export and import
5. NDP
6. Green GNP
7. Final goods approach
8. Expenditure Method
9. Theoretical difficulty

[C] Give economic terms.

1. The gross market value of all final goods and services produced within a country in a year.
2. When depreciation is deducted from Gross National Product (GNP).
3. When the flow of income is circulated between households and business firms.
4. When value of total production of goods and services in a year is expressed in money term.
5. It is difference between export value and ) import value.
6. Organisation doing estimation of National Income.
7. In this approach value of final goods and services is considered.
8. In this approach value is added at each stage of the production process.
9. It is also known as factor cost method.
10. It is a sum/ total of income received by all ) factors of production.
11. In this method national income is R + W + I + P + MI + (X – M)
12. It is a method in which the total expenditure incurred by the society in a particular year is added together.
13. To avoid double counting these goods and services not considered while counting NI.
Answers:

1. Gross Domestic Product (GDP)
2. Net National Product (NNP)
3. Two sector economy
4. National Income (NI)
5. Net income from abroad (X – M)
6. Central Statistical Organization (CSO)
7. Final Goods Approach
8. Value Added Approach
9. Income method
10. Income method
11. Income method
12. Expenditure Method
13. Intermediate goods

(D) Find the odd word out.

1. Members of NIC (National Income Committee) :
Prof. P.C. Mahalanobis, Prof.D.R. Gadgil, Dr .V.K.R.V. Rao, Kaushik Basu.
Answer:
Kaushik Basu2. Features of NI:
Marco economic concept, Money value, Static concept, Flow concept.
Answer:
Static concept3. Three sector economy :
Foreign sectors, Household, Business Firms, Government sector.
Answer:
Foreign sector

4. Concepts of NI:
GDP, NDP, NIC, GNP.
Answer:
NIC

5. Concept of Green GNP :
Sustainable economic development, equitable distribution of benefits, Promotes economic welfare, environmental degradation.
Answer:
Environmental degradation

6. Methods of measurement of NI:
Output method, Point method, Income method, Expenditure method.
Answer:
Point Method

7. In India output is applied to :
agriculture, mining and manufacturing, transport, handicrafts.
Answer:
transport

8. In India output is not applied for :
agriculture, transport, commerce, communication.
Answer:
agriculture

9. Income method excludes :
transfer income, unpaid services, revenue from direct taxes, imputed value of production kept for self-consumption.
Answer:
imputed value of production kept for self-consumption

10. Expenditure method consist of: Consumption expenditure, Investment expenditure, Government expenditure, Expenditure on raw material.
Answer:
Expenditure on raw material

11. Income method is used in :
USA, UK, Germany, India.
Answer:
India

12. Theoretical Difficulties :
Income of foreign firms, Valuation of inventories, Valuation of government services, Transfer income.
Answer:
Valuation of inventories

13. Practical difficulties :
Capital gain/loss, Depreciation, Problem of double counting, Illegal income.
Answer:
Illegal income

14. To obtain NI, these should be excluded : Sales tax, Direct tax, Subsidies, Indirect tax
Answer:
Subsidies

15. Transfer income is :
Pension, Gifts, Rent, Unemployment ( allowance.
Rent

(E) Complete the following statements.

1. National income is the net aggregate value which does not include …………….
Answer:
depreciation

2. In India, the financial year from 1st April to 31st March is used to express …………….
Answer:
National Income

3. Inclusion of value of intermediate goods leads to …………….
Answer:
double counting

4. Services of housewives are known as …………….
Answer:
unpaid services

5. In India, the calculation of NI is done by …………….
Answer:
Central Statistical Organisation

6. ……………. method is rarely used to calculate NI.
Answer:
Expenditure Method

7. National income is studied by ……………..
Answer:
Macro economists

8. ……………. refers to wear and tear of capital assets.
Answer:
Depreciation

9. In NI value of unpaid services are …………….
Answer:
ignored / excluded

10. ……………. approach is used to avoid double counting.
Answer:
Value added approach

11. The value of only final goods and services produced in primary, secondary and tertiary sector are included in …………….
Answer:
Final goods approach

12. ……………. sector includes exchange activities without the use of money.
Answer:
Non monetised sector

13. Due to lack of occupational specialization, the calculation of national income becomes difficult by ……………. method.
Answer:
the Output Method

14. Estimating the exact national income due to changing price level is ……………. difficulty.
Answer:
(17) theoretical difficulty

15. The expenditure incurred on law and order, defence, education, etc. is called as …………….
Answer:
Government Consumption expenditure

16. While estimating NI, expenditure on final goods and services, subsidies should be …………….
Answer:
(19) included

17. ……………. leads to overestimation of the national income.
Answer:
Double counting

(F) Choose the wrong pair :

I.

Group ‘A’	Group ‘B’
Transfer income	pension/ gifts
National Income	flow concept
Gross Domestic Product (GDP)	C + I + G + (X – M) + (R-P)
CSO	Estimation of NI

Answer:
Wrong pair : Gross Domestic Product C+I+G+(X-M) +(R-P)

II.

Group ‘A’	Group ‘B’
National Income	Money value of goods and services
Unemployment allowances	Transfer payment
NNP	GNP – Depreciation
Income Method	Output method

Answer:
Wrong pair method : Income Method – Output

III.

Group ‘A’	Group ‘B’
The Output method	Product method
India used	Expenditure method
USA, UK	Income method
Illegal Income	Theoretical difficulty

Answer:
Wrong pair : India used – Expenditure method

(G) Choose the correct pair

I.

Group ‘A’	Group ‘B’
Three sector economy	Households, business firms, foreign sector
National income	Money value of final goods and services
Output method	Income method
NNP	GDP – Depreciation

Answer:
(2) National Income – Money value of final goods and services.

II.

Group ‘A’	Group ‘B’
Expenditure Method	Inventory method
GDP	C + I + G + (X-M) + (R-P)
National income	Micro economic concept
Unpaid services	Services of housewife

Answer:
(4) Unpaid services – Services of housewife

III.

Group ‘A’	Group ‘B’
Output method	The final goods approach
Income method	Product method
Expenditure method	NI = C + I + G
Illegal income	income from taxes

Answer:
(1) Output method The final goods approach.

IV.

Group ‘A’	Group ‘B’
National Income Committee	1956
Financial year	1st April to 31st March
Income Method	NI = Rent + Wages + Interest + Profit + MI + (X-M)
Expenditure Method	NI + C + I + G + (X – M)

Answer:
(3) Income Method – NI = Rent + Wages + Interest + Profit + MI + (X – M)

(H) Assertion and Reasoning

Question 1.
Assertion (A) – National dividend is that part of objective income of the community including of course income derived from abroad which can be measured in money. Reasoning (R) – This is given by Prof. A. C. Pigou.
(1) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).

Question 2.
Assertion (A) – National income is the micro economic concept.
Reasoning (R) – Micro economics deals with aggregate.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(iv) (A) and (R) both are false.

Question 3.
Assertion (A) – National income is the flow concept.
Reasoning (R) – It considers the production of goods and services in the economy during a year.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).

Question 4.
Assertion (A) – In two sector model money flows from the firms to the households in the form of rent, wages, interest.
Reasoning (R) – Households purchase goods and services from firms by using this money.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).

Question 5.
Assertion (A) – NDP = GDP – Deprecation
Reasoning (R) – To get exact value of goods and services depreciation is deducted.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).

Question 6.
Assertion (A) – In output method value of final goods and services is considered.
Reasoning (R) – In output method value of intermediate goods also considered.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(iii) (A) is true but (R) is false.

Question 7.
Assertion (A) – Value added approach is the difference between the value of final output and inputs at each stage of production.
Reasoning (R) – To avoid double counting value added approach is used.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).

Question 8.
Assertion (A) – While estimating NI indirect taxes included in the market prices are to be deducted.
Reasoning (R) – Indirect taxes are deducted to get accurate estimation of NI.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).

Question 9.
Assertion (A) – Output method is more reliable.
Reasoning (R) – It is used in all developed countries.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the } correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(iv) (A) and (R) both are false.

Question 10.
Assertion (A) – All unpaid services are ) excluded from NI.
Reasoning (R) – It’s difficult to get exact) value of unpaid services.
(i) Both (A) and (R) are true and (R) is the l correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the l correct explanation of (A).

Question 11.
Assertion (A) – There are no uniform, common standard rates of depreciation
applicable to the various capital assets.
Reasoning (R) – It is easy to make correct deduction for deprecation.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(iii) (A) is true but (R) is false.

Question 12.
Assertion (A) – The small producers do not keep an account of their production. Reasoning (R) – Most of the small producers are ignorant and illiterate.
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).
(ii) Both (A) and (R) are true but (R) is not the correct explanation of (A).
(iii) (A) is true but (R) is false.
(iv) (A) and (R) both are false.
Answer:
(i) Both (A) and (R) are true and (R) is the correct explanation of (A).

2 [A]. Identify and Explain the following concepts:

Question 1.
Suman is a math teacher by profession She also taught her son math at home.
Answer:
Concept: Unpaid services
Explanation : The services provided out of love, affection, mercy, sympathy and charity ( are not included in NI as they are not paid { (12) for. The value of unpaid services is not counted in NI.
Thus, Suman teaching math to her son is treated as unpaid service.

Question 2.
Renu paid ₹ 500 for her chest *X’ ray in $ private hospital and for the same ‘X’ ray she paid ₹ 50 in government hospital.
Answer:
Concept: Valuation of government services.
Explanation : The government provides various services lower than market price. So it is difficult to get real value of these while estimating NI.

Question 3.
Anil is a graduate but he is unemployed and receives ₹ 600 from the government.
Answer:
Concept: Unemployment Allowances. Explanation : It is considered as a transfer payment which is not included in NI.

Question 4.
Reena studies in government medical college and pays annual fees of ₹ 80,000 per year and Meena who studies in private medical college and pays annual fees of ₹ 8,00,000.
Answer:
Concept: Valuation of government services.
Explanation : The government provides various services lower than market price. It is difficult to get real value of such services while estimating NI.

Question 5.
Pooja, a cook earns ₹ 8,000 per month and she also cooks food in her house.
Answer:
Concept: Unpaid services.
Explanation : The services provided out of love, affection, mercy, sympathy and charity are not included in NI as they are not paid for. The value of unpaid services is not counted in NI.

Question 6.
Suresh regularly purchases sanitizer for ₹ 60, owing to the ‘Corona virus’ outbreak, it disappeared from the market and after few days it was sold at ₹ 100.
Answer:
Concept: Illegal income (Black Marketing)
Explanation: Illegal income is not included in NI. There will be underestimation of NI as income from illegal activities are not included.

Question 7.
To increases the production, Ambhuja cement recently purchased the machinery worth ₹ 2000 crores.
Answer:
Concept: Private Investment expenditure (I).
Explanation : It is the investment made by private businessman on capital goods like machinery, technology, plants, etc.

Question 8.
Rahul bought a car on June, 2020 from his friend Rajesh for 1 1,20,000 which is manufactured in
Answer:
Concept: Second hand goods.
Explanation : Expenditure on second hand goods should be excluded from NI. Such goods were accounted for in the year when it was produced and sold.

Question 9.
India incurred ₹ 40,000 crores to purchase missile systems S-400 from Russia.
Answer:
Concept : The Government’s Consumption expenditure.
Explanation : Government Consumption expenditure refers to the expenditure incurred by the government on various administrative services like, law and order, defence, education, health, etc.
Such government expenditures are included while calculating National Income by expenditure method.

Question 10.
The government of India is incurring ₹ 1600 crore on Delhi-Mumbai expressway which will complete by 2023 of the economy.
Answer:
Concept : The Governments Investments expenditure.
Explanation : Government Investment expenditure refers to the expenditure incurred by the government on creating infrastructural facilities like construction of roads, railways, bridges, dams, canals, etc. Such government expenditures are included while calculating National Income by expenditure method.

(B) Distinguish between

Question 1.
Gross National Product (GNP) and Gross Domestic Product (GDP).
Answer:
Gross National Product (GNP):

1. Gross National Product refers to gross money value of all final goods and services produced in the country during one accounting year, including net income from abroad.
2. GNP = C + I + G + (X – M) + (R – P)
3. GNP includes income earned by Indian Nationals within or outside the country.

Gross Domestic Product (GDP):

1. Gross Domestic Product refers to gross money value of all final goods and services produced within the domestic boundaries of a country during one accounting year.
2. GDP = C + I + G + (X-M)
3. GDP does not include income earned by Indian national outside the country.

Question 2.
Net National Product (NNP) and Net Domestic Product (NDP).
Answer:
Net National Product (NNP):

1. NNP is the net value of all final goods and services produced in an economy for one accounting year. It includes income from abroad.
2. It includes income earned by Indian Nationals within and outside the country.
3. NNP = C + I + G + (X – M) + (R – P) – Depreciation
4. NNP will be greater than NDP if (R – P) is positive.

Net Domestic Product (NDP):

1. NDP is net value of all final goods and services produced within the domestic boundaries of the country.
2. It does not include income earned by the Indian Nationals outside the country.
3. NDP = C + I + G + (X-M)- Depreciation
4. NDP will be less than NNP if (R – P) is positive and it can be more than NNP if (R – P) is negative.

Question 3.
Output Method Or Product Method and Income Method Or Factor Cost.
Answer:
Output Method Or Product Method:

1. According to the product or output method, National Income is estimated by adding up the value of all final goods and services produced in the country during one year.
2. NI = C+I+G+(X-M)+(R – P) – Depreciation – Income Tax + Subsidies
3. In India, this method is applied to agriculture, mining and manufacturing.
4. Here we look at National Income from production side.
5. In this method we deduct indirect tax and then add subsidies to arrive at National Income at Factor Cost from Market Price.

Income Method Or Factor Cost:

1. According to Income method the National Income is estimated by adding the factor Incomes that accrue to factors of production by way of rent, wages, interest and profit.
2. NI = R + W + I + P + MI + (X-M) + (R-P) – Depreciation – Transfer Income.
3. In India this method is used by National Income Committee in trade, transport, professionals, liberal arts, public administration.
4. Here we look at National Income from distribution side.
5. This method is a direct method as we arrive at National Income at factor cost.

Question 4.
Gross National Product (GNP) and Net National Product (NNP). (Feb. ‘16; Oct. ‘15)
Answer:
Gross National Product (GNP):

1. Gross National Product refers to gross money value of all final goods and services produced in an economy during a year. It includes net income from abroad.
2. Depreciation cost of capital assets are included.
3. GNP = C + I + G + (X-M) + (R-P)Or GNP = NNP + Depreciation
4. GNP value does not give us a true picture of the net increase in the production of the economy.
5. It is a wider concept. It includes NNP.
6. GNP will be greater than NNP.

Net National Product (NNP)

1. Net National Product refers to the net money value of all goods and services produced in an economy during a year. It includes net income from abroad.
2. Depreciation cost of capital assets are not included.
3. NNP = GNP – Depreciation Or
   NNP = C + I + G + (X-M) + (R – P) –  Depreciation
4. NNP is a better measure of National Income. It is a better index of judging the progress of the economy at any time.
5. It is narrow concept. It is a part of GNP.
6. NNP will be less than GNP.

Question 5.
Illegal Income and Transfer Income.
Answer:
Illegal Income:

1. Illegal income means income which is earn from illegal activities.
2. E.g. Income from gambling, black marketing, theft, smuggling, etc.

Transfer Income:

1. Transfer income means money from the government in the form of benefits.
2. E.g. income from pension, gift, unemployment allowance, etc.

Question 6.
Two Sector economy and Three Sector economy.
Answer:
Two Sector economy:

• In this economy flow of goods and money is circulated in households and business firms.
• Symbolically – Y = C + I

Three Sector economy:

• In this economy flow of goods and money is circulated in households, business firms and government sector.
• Symbolically – Y= C + I + G.

Question 7.
Three Sector economy and Four Sector economy.
Answer:
Three Sector economy:

1. In this economy, flow of goods and money is circulated in households, business firms and government sector.
2. Symbolically – Y = C + I + G

Four Sector economy:

1. In this economy, flow of goods and money is circulated in households, business firms, government sector and foreign sector.
2. Symbolically – Y= C + I + G + (X-M)

Question 8.
Income Method and Expenditure Method.
Answer:
Income Method:

1. It is the sum of income earn by all factors of production in a year.
2. In this method, national income is estimated from the distribution side
3. Symbolically – NI = R + W + I + MI + (X-M)
4. This method is extremely popular in developed countries.

Expenditure Method:

1. It is the sum of expenditure incurred by private sector and government on consumption and investment in a year.
2. In this method, national income is estimated from the expenditure side.
3. Symbolically -NI = C + I + G + (X-M) + (R-P)
4. This method is very rarely used by any country.

Question 9.
Closed Economy and Open Economy.
Answer:
Closed Economy:

1. It is an economy which is not open to international trade and foreign investment.
2. In a closed economy only the values of goods and services produced within the country are considered in the N.I. estimate.
3. Net exports and net factor income from abroad are not included.
4. GNP = GDP + C + I + G.

Open Economy:

1. It is an economy which is open to international trade and foreign investment.
2. In an open economy the values of goods and services produced within the country as well as net exports and net factor income from abroad are also considered in N.I. estimate.
3. Net exports and net factor income from abroad are included.
4. GDP(MP) = C + I + G + (X – M)
   GNP(MP) = GDP + (R – P)
   = C + I + 0 + (X – M) + (R – P)

Question 10.
Product / Output Method and Expenditure Method.
Answer:

Output Method Or Product Method:

1. According to the product or output method, National Income is estimated by adding up the value of all final goods and services produced in the country during one year.
2. NI = C+I+G+(X-M)+(R – P) – Depreciation – Income Tax + Subsidies
3. In India, this method is applied to agriculture, mining and manufacturing.
4. Here we look at National Income from production side.
5. In this method we deduct indirect tax and then add subsidies to arrive at National Income at Factor Cost from Market Price.

Expenditure Method:

1. It is the sum of expenditure incurred by private sector and government on consumption and investment in a year.
2. In this method, national income is estimated from the expenditure side.
3. Symbolically -NI = C + I + G + (X-M) + (R-P)
4. This method is very rarely used by any country.

3. Answer the following questions:

Question 1.
Explain the income method of measuring National Income.
Answer:
Meaning:
In general sense of the term ‘National Income’ refers to the total money value of all final goods and services produced in the country during a period, usually one year. It includes net income from abroad. But does not include depreciation.

Definitions:

• Prof. AC. Pigou: ‘The national dividend is that part of the objective income of the community including of course income derived from abroad, which can be measured in money.”
• Prof. Irving Fisher: “National dividend or income consists solely of services as received by ultimate consumers whether from their material or from their human environments.”
• National Income Committee: “A National Income estimate measures the volume of commodities and services turned out during a given period counted without duplication.” Here, the National Income is calculated without double counting.

Question 2.
Explain the expenditure method of measuring National Income.
Answer:

(B) Expenditure Method :
This method also known as outlay method. NI = C + I + G + (X – M) + (R – P)
National Income can also be calculated by adding up the expenditure incurred on purchase of final goods and services. We can get National Income by summing up all consumption expenditure, investment expenditure made by all individuals, firms as well as the government of a country during a year.

• Consumption Expenditure (C) : It includes all expenditure incurred on goods and services by households during the year. It includes expenditure mostly on durable and non-durable goods, which are consumed by the consumers. E.g. food, medical care, clothing, car, computer and services, etc.
• Investment Expenditure (I) : It refers to the investment made by private businessman on capital goods like machinery, plants, factories, warehouses, etc.
• Government Expenditure on goods and services (G) : Government expenditure refers to expenditure on consumption and investment –
  • Consumption expenditure : It refers to expenditure incurred on various administrative services like law and order, defence education, generation and distribution of electricity.
  • Investment expenditure : It refers to expenditure incurred by government on construction of roads, railways, dams, canals, etc.
• Net Exports (X – M): It refers to difference between exports and imports of the country. If the exports are more than imports then net exports will be positive, it is called Trade Surplus and if imports are greater than exports, the net exports will be negative, it is called as Trade Deficit.
• Net Receipts (R-P) : It is the difference between expenditure incurred by foreigners in the country (R) and expenditure incurred abroad by Nationals (P). Net Receipts can also be Positive or Negative.
  Net National Expenditure = NNE = C + I + G + (X – M) + (R – P) – Depreciation. NNPFC or NI = C + I + G + (X -M) + (R -P) “Depreciation “ Indirect Tax + Subsidies.

Precautions :
The following precautions should be taken while estimating National Income.

• To avoid double counting take the expenditure incurred only on final goods and services.
• Government expenditure on transfer payments to be excluded like unemployment allowances, old age pension etc.
• Expenditure on second hand goods like furniture, house, land and financial assets { like shares, bonds, etc. should be excluded.
• Exclude expenditure incurred on purchase of financial assets such as shares, bonds, etc.
• Deduct indirect tax and add subsidies. Out of these methods, output method and income method are extensively used. Expenditure method is rarely used because of its practical difficulties.
  In India, the Central Statistical Organisation (CSO) adopts a combination of output method and income method to estimate N.I. of India.

Question 3.
Give the definitions of National Income.
Answer:
Meaning:
In general sense of the term ‘National Income’ refers to the total money value of all final goods and services produced in the country during a period, usually one year. It includes net income from abroad. But does not include depreciation.

Definitions:

• Prof. AC. Pigou: ‘The national dividend is that part of the objective income of the community including of course income derived from abroad, which can be measured in money.”
• Prof. Irving Fisher: “National dividend or income consists solely of services as received by ultimate consumers whether from their material or from their human environments.”
• National Income Committee: “A National Income estimate measures the volume of commodities and services turned out during a given period counted without duplication.” Here, the National Income is calculated without double counting.

4. State with reasons whether you agree or disagree with the following statements:

Question 1.
National Income is important to formulate only economic policies.
Answer:
No, I do not agree with this statement.
National Income data is important for many other purposes, like –

• For the Economy : National Income data are very important for marco economic analysis and performance of the economy.
• Economic Planning: The data of National Income is very important tools for long term and short term economic planning.
• Economic Research: The data of National [ Income is very useful to the research students to study aggregate consumption expenditure, investment expenditure, etc.
• Speed of Economic Growth : National Income makes it possible to know the trends or speed of the economic growth of our ( country in relation to previous years.

Question 2.
Income from second hand sale of goods is excluded from National Income.
Answer:
Yes, I agree with this statement.

• National Income includes only the money value of final goods and services produced in ( the current year.
• Income from sale and purchase of second hand goods is not included in National Income because these goods are not a part of current years production. Their value was included in the National Income of that year in which they were produced.
• As the wealth of the country remains the same if they are included in the current years National Income it will lead to double counting.
• So, National Income figures will get inflated due to over estimation.

Question 3.
National Income at factor cost includes subsidy.
Answer:
Yes, I agree with this statement.

• National Income at factor cost is the income earned by the factor owners (landlord, labourer, capitalist) in the course of contributing to the country’s output.
• NI(FC) = C + I + G + (X – M)+ (R – P) – Depreciation – Indirect Tax + Subsidies
• Subsidies is a negative tax. It is a sought of concession or discount given by the government to the consumers and producers.
• Subsidies are paid by the government to the firms / producers.
• Also the goods are sold at a price lower than their cost.
• Subsidies reduce the price of product below the factor cost. So to arrive at N.I. at factor cost we add subsidies.

Question 4.
National Income estimates are not accurate in India.
Answer:
Yes, I agree with this statement.
There are many statistical difficulties faced in the estimation of National Income due to which N.I. estimates are not accurate. They are as follows :

• There is the danger of double counting by including the value of intermediate goods.
• Inadequate and unreliable information regarding income and expenditure leads to inaccuracy in estimating N.I.
• In India, people are illiterate and ignorant, so they do not maintain proper accounts.
• To evade tax people do not reveal their exact income.
• The sources from which data are obtained are not absolutely reliable.
• Statistical staff are untrained and inefficient.

Question 5.
Old age pension is transfer income.
Answer:
Yes, I agree with this statement.

• Transfer Income are income received by individuals without contributing anything to the current years production of goods and services. It is a flow of money without a reverse flow of goods or services.
• Old age pension is received by a person after he retires from work.
• To get this income tlje person actually does not contribute anything to production of goods and services during that period.
• Old age pension is income transferred from the government.
• So it is a government expenditure.
• Transfer income are included in personal income. But they are not included in National Income because such payments do not result in any addition to the total production of goods.

Question 6.
Paid services are included in National Income.
OR Unpaid services are not included in National Income. (Mar. ‘15; Oct. ‘15)
Answer:
Yes, I agree with this statement.

• In economic sense paid services refer to economic production which means they are production of those goods and services which are meant for sale and have market value.
• Paid services are marketable. They have exchange value. We can determine its price and so it can be included in National Income.
• Unpaid services cannot be marketed so they cannot be included in National Income. Although these services contribute to human welfare.
• E.g. service of housewife. It is non-economic production, which is not marketable.
• National Income is the sum of money value of all goods and services produced during the year by the resources of a country.

Question 7.
National Income is an important tool to measure the overall performance of the economy.
OR
The concept of National Income has an important place in Economic development.
Answer:
Yes, I agree with this statement.

• National Income is one of the important indicators of economic growth and development.
• National Income is a macro variable that represents the economy as a whole.
• When there is an increase in National Income it indicates that the country’s production of goods and services have increased, employment increases, trade with rest of the world increases.
• When National Income of a country increases at a higher rate than the rate of increase in population, it leads to improvement in the standard of living and welfare of the people.
• The Per Capita Income also increases when  National Income increases.
• Therefore, National Income is an important tool to measure the overall performance of the economy.

Question 8.
The services of housewife (unpaid services) is included in National Income.
Answer:
No, I do not agree with this statement.
OR
Services of housewives are excluded from National Income.
Answer:
Yes, I agree with this statement.

• The National Income is the sum of money value of all goods and services produced during the year by the resources of a country.
• But the goods and services which do not have exchange value or market value are not included in National Income as they are non-economic production.
• Service of housewife is not considered an economic activity as it is non – economic production and so it does not have exchange value or market value.
• Housewife is not paid by family members.
• Therefore, the service of housewife is not included in National Income but the service of a maid servant is included.

Question 9.
Illegal income is not included in National Income.
Answer:
Yes, I agree with this statement.

• The existence of a parallel or black economy is a common feature of most of the economies.
• Productive activities in this sector are either concealed or under reported and as a result the income generated remain unreported. It is rather difficult to estimate this income correctly. So they are not included in National Income.
• For example income originating from activities as smuggling, black-marketing, gambling, selling harmful drugs, etc. are excluded from National,Income.
• Many rich people, businessmen and landlords hide their property and wealth. No authorised registration is available for the income received so they are not included.

Question 10.
Transfer income is included in National Income.
Answer:
No, I do not agree with this statement.
OR
Transfer Income cannot be included in National Income.
Answer:
Yes, I agree with this statement.

• Transfer income is income received by individuals without contributing to the current years production of goods and services.
• Transfer income received by people in the form of old age pension, gifts, lottery prize etc. are not included in National Income.
• These incomes are included in Personal Income but not in National Income.
• All transfer income are actually earned by some other people, by contributing to production originally and then transferred to another.
• If such incomes are counted at both places two times, there will be a double counting.
• Therefore, to avoid double counting and to get accurate estimation, transfer incomes are not included in National Income.
  National Income includes only income from production of goods and services.

Question 11.
National Income is a stock / reserve concept.
Answer:
No, I do not agree with this statement.
OR
National Income is not a stock. It is a flow concept.
Answer:
Yes, I agree with this statement.

• National income is a flow concept.
• National income is expressed per year.
• National income refers to money value of all goods and services produced by the economy in a year.
• It considers the production of current year and not previous year.

5. Study the following table / figures / passages and answers :

1. Subdivided Bar Diagram
Diagram 1 : Share of GDP by Sector for Selected Nations (2017)

Question 1.
Which are the sectors contributing in National Income / GDP?
Answer:
There are three sectors contributing in GDP – agriculture, industry and tertiary (services) sector.

Question 2.
In the United States GDP, which sectors contribution is maximum and how much percent?
Answer:
The service (tertiary) sector’s contribution is maximum in United States GDP. It was 80%.

Question 3.
In which country, contribution of primary ‘ sector (agriculture) is lowest in GDP?
Answer:
UK (United Kingdom) and Germany’s; contribution of primary sector is lowest in GDP.

Question 4.
How much is the share of agriculture in India’s National Income in the year 2017?
Answer:
In the year 2017, the share of agriculture was 15.5%.

Question 5.
In which country, the share of industry is maximum and how much percent?
Answer:
In China, the share of industry is maximum. It is 40.5%.

Question 6.
Give your opinion on sectorwise contribution in India’s GDP.
Answer:
In India, share of agriculture sector is quite high as compared to developed countries. There is need to reduce the share of agriculture in GDP. The industry and service sector should be developed so their contribution in the GDP will rise.

2. Top 10 Economies in the world in terms of GDP at current US $ trillion.

Data Source : World Economic Outlook, October 2019 database

Note : IMF’s estimate, A indicates improvement in rank, v indicates drop in rank and – indicates unchanged rank

Question 1.
Which country has highest GDP in the world?
Answer:
United State of America has the highest GDP in the world.

Question 2.
Which country has the least GDP in the world?
Answer:
Korea has the least GDP in the world.

Question 3.
At what position does India stand with respect to GDP rates?
Answer:
India stands at 5th position with respect to ) GDP rates.

Question 4.
Find out the difference in China’s GDP in the year 2017 and 2018.
Answer:
The China’s GDP has increased by 1.3 US $ trillion in the year 2018 as compared to the year 2017.

Question 5.
By how much India’s GDP has increased in the year 2017-2018.
Answer:
There is no increase in India’s GDP in the year 2017-18. India’s GDP is constant.

Question 6.
Given your opinion on India’s GDP.
Answer:
India’s is a developing economy, but it still stands at the 5th position in the worlds GDP’s.

India should focus on increasing the production of goods and services specially
from secondary and tertiary sector which will help to increase the GDP.

(3) Circular Flow of Income.

Question 1.
What does this diagram represent?
Answer:
This diagram represents model of four sector economy.

Question 2.
Which sectors are included in this type of economy?
Answer:
It includes households, firms, government and foreign sector.

Question 3.
What role does the government play in this economy?
Answer:
The government is playing very important ) role by incurring expenditure on consumption and investment. The government is also S collecting tax from household, business firm and through import.

Question 4.
Give your opinion on overseas or foreign sector.
Answer:
In four sector economy, foreign sector is playing important role. This is known as open economy which helps to earn foreign exchange, promote economic development, availability of imported goods, etc.

6. Answer in detail;

Question 1.
What is national income? Explain theoretical conceptual difficulties in the calculation of national income.
Answer:
National income means money value of goods and services produced in the country in a year.
According to National Income committee:
“A national income estimate, measures the volume of goods and services turned out during a given period without duplication. There are many practical difficulties in the measurement of NI.

• Transfer payment: If it included in national income then there will be overestimation of NI. E.g. pension, gifts, unemployment allowances, etc. are excluded.
• Unpaid services : The value of unpaid services are not included in national income as they are not paid for. E.g. services of housewife.
• Illegal income : The income from illegal activities are not included in NI. E.g. black marketing, smuggling.
• Production for self-consumption: It is very difficult to get data and value of goods kept for self-consumption as they do not enter market.
• Income of foreign firms : Income of foreign firm should be included in the national income of the country where the firm undertakes production work. But the profit earn by these firms are transferred to their home own country.

Question 2.
Explain the difficulties in measuring National Income.
Answer:
National income means money value of goods and services produced in the country in a year.
According to National Income committee:
“A national income estimate, measures the volume of goods and services turned out during a given period without duplication. There are many practical difficulties in the measurement of NI.

(A) Theoretical difficulties

• Transfer payment: If it included in national income then there will be overestimation of NI. E.g. pension, gifts, unemployment allowances, etc. are excluded.
• Unpaid services : The value of unpaid services are not included in national income as they are not paid for. E.g. services of housewife.
• Illegal income : The income from illegal activities are not included in NI. E.g. black marketing, smuggling.
• Production for self-consumption: It is very difficult to get data and value of goods kept for self-consumption as they do not enter market.
• Income of foreign firms : Income of foreign firm should be included in the national income of the country where the firm undertakes production work. But the profit earn by these firms are transferred to their home own country.

(B) Practical Difficulties or Statistical Difficulties:

• Problem of double counting: In case of certain goods it is difficult to distinguish properly between final goods and intermediate goods. That’s why problem of double counting arises e.g. flour is final goods for housewife, but it is intermediate goods for the bakery.
• Existence of non-monetised sector: In India large non-monetised sector exists in rural area specially in agriculture. In agriculture, many places goods and services are exchanged with goods that’s why it is difficult to count in national income.
• Inadequate and unreliable data: Because of illiteracy it is difficult to get adequate and reliable data from unorganised sector, small enterprises, agriculture, etc.
• Depreciation: Its difficult to measure exact value of depreciation. There are no uniform common accepted standard rates of depreciation applicable to the various capital assets.
• Capital gain or loss: Due to capital gain there is overestimation and due to capital loss there is underestimation of national income.
• Illiteracy and ignorance: Majority of small producer in developing counties are illiterate and ignorant and are not able to keep accounts of their productive activities.
• Lack of systematic, occupational classification: There is lack of systematic occupational classification, which makes the calculation of national income difficult. Especially in rural areas where many villagers work on farms for some time and also take some other job during offseason.
• Untrained and incompetent staff: Due to untrained and incompetent staff, accurate and timely, information cannot be obtained.

Question 3.
What is National Income? Explain the Output method of measuring National Income.
Answer:
Product Method or Output Method: This method is also called as Inventory Method.
According to this method economy is divided into various sectors like agriculture, mining, manufacturing, small enterprises, commerce, transport, communication, etc.

National income by this method can be calculated by either valuing all final goods and services
produced during a year at their market price or by adding up all values at each higher stage of
production, until these products are turned into final products.

In output method there are two approaches to measure national income.

(1) Final Goods Approach I Final Product Approach : According to this approach, value of all final goods and services produced in primary, secondary and tertiary sector are included and the value of all intermediate transactions are ignored.

2. Value Added Approach I Value Added Method: To avoid double-counting, the value-added approach is used to estimate the National Income. According to this method, it is necessary to obtain the total of value-added at each stage in the manufacture of a commodity to arrive at Gross National Product. The value-added method can be explained by means of a simple example.

(a) In the above example, value of groundnut with shell is 50, after removing shells value of groundnut is 80, after crushing groundnut the value is 120 and when oil is packed in the packets its value is 150.
To avoid double-counting either the value of final output or the value – added should be taken in estimation of National Income.

The output method is widely used in the underdeveloped countries. In India, this method is applied in agriculture, mining and manufacturing sector.

Precautions:

• Avoid Double Counting: The value of only final goods and services must be considered and not the value of raw – materials or intermediary goods, etc.
• Self Consumption Goods: Goods used for self-consumption by farmers should be included in National Income.
• Price Level Changes to be considered: The values of national output must be expressed in terms of prices in some base year to know the national output in real terms i.e. N.I. at constant price.
• Net Income from Abroad: Care should be taken to include net income from abroad in National Income.
• Depreciation: Depreciation of capital assets should be deducted from the value of gross investment during the year.
• Indirect Taxes and Subsidies: To get National Income, deduct the indirect tax from the market price and add subsidies.
• Second-Hand Goods: Sale and purchase of second-hand goods should be ignored as it is not a part of current production.

Question 4.
Explain the various method of measuring National Income. ?
Answer:
National Income is macro economic concept. National Income means money value of goods and services produced in the country in a year. There are three methods to measure national income.
(1) The Output Method,
(2) The Income Method,
(3) The Expenditure Method.

(A) The Income Method : This method is also known as factor cost method. According to this method national income is the sum of income received by all factors of production in a year. So national income is the income received by all the citizens of the country in a year. In income method national income studied from the distribution side. According to income method national income or GNP is
NI = R + W + I + P + MI + (X – M)

• Rent (R) : Rent and Royalty is usually treated as the payment for the land, building, machines that are rented.
• Wages (W) : It includes wages and salaries earned by labour as well as it includes commission, bonus, social security payments, fringe benefits, etc.
• Interest (I) : Interest is the payment for using the services of capital. It includes interest paid by banks, insurance companies etc.
• Profit (P) : It includes the profit of private and public sector companies.
• Mixed Income (MI) : It is the income which is earned by self-employed. They earn income through various sources like wages for effort put, rent on own property, interest on own capital, etc.
• Net Exports (X – M) : It is the difference between export and imports.

Precautions :

• Transfer payment : It should not be included in national income. E.g. pension, gifts, unemployment allowances, lottery prize, etc.
• Unpaid services : It should not be included in national income. E.g. services of housewife, teacher teaching her own child, etc.
• Second hand goods : The income from sale of second hand goods should not be included.
• Financial asset : The income from sale of shares and bonds should not be included in national income.
• Tax revenue : The revenue of government through taxes should not be included in national income.
• Undistributed profits of companies, income from government property and profits from public enterprise should be included.
• Imputed value of production kept for self consumption and rental value of owner occupied houses should be included in national income.

(B) Expenditure Method :
This method also known as outlay method. NI = C + I + G + (X – M) + (R – P)
National Income can also be calculated by adding up the expenditure incurred on purchase of final goods and services. We can get National Income by summing up all consumption expenditure, investment expenditure made by all individuals, firms as well as the government of a country during a year.

• Consumption Expenditure (C) : It includes all expenditure incurred on goods and services by households during the year. It includes expenditure mostly on durable and non-durable goods, which are consumed by the consumers. E.g. food, medical care, clothing, car, computer and services, etc.
• Investment Expenditure (I) : It refers to the investment made by private businessman on capital goods like machinery, plants, factories, warehouses, etc.
• Government Expenditure on goods and services (G) : Government expenditure refers to expenditure on consumption and investment –
  • Consumption expenditure : It refers to expenditure incurred on various administrative services like law and order, defence education, generation and distribution of electricity.
  • Investment expenditure : It refers to expenditure incurred by government on construction of roads, railways, dams, canals, etc.
• Net Exports (X – M): It refers to difference between exports and imports of the country. If the exports are more than imports then net exports will be positive, it is called Trade Surplus and if imports are greater than exports, the net exports will be negative, it is called as Trade Deficit.
• Net Receipts (R-P) : It is the difference between expenditure incurred by foreigners in the country (R) and expenditure incurred abroad by Nationals (P). Net Receipts can also be Positive or Negative.
  Net National Expenditure = NNE = C + I + G + (X – M) + (R – P) – Depreciation. NNPFC or NI = C + I + G + (X -M) + (R -P) “Depreciation “ Indirect Tax + Subsidies.

Precautions :
The following precautions should be taken while estimating National Income.

• To avoid double counting take the expenditure incurred only on final goods and services.
• Government expenditure on transfer payments to be excluded like unemployment allowances, old age pension etc.
• Expenditure on second hand goods like furniture, house, land and financial assets { like shares, bonds, etc. should be excluded.
• Exclude expenditure incurred on purchase of financial assets such as shares, bonds, etc.
• Deduct indirect tax and add subsidies. Out of these methods, output method and income method are extensively used. Expenditure method is rarely used because of its practical difficulties.
  In India, the Central Statistical Organisation (CSO) adopts a combination of output method and income method to estimate N.I. of India.

Product Method or Output Method: This method is also called as Inventory Method.
According to this method economy is divided into various sectors like agriculture, mining, manufacturing, small enterprises, commerce, transport, communication, etc.

National income by this method can be calculated by either valuing all final goods and services
produced during a year at their market price or by adding up all values at each higher stage of
production, until these products are turned into final products.

In output method there are two approaches to measure national income.

(1) Final Goods Approach I Final Product Approach : According to this approach, value of all final goods and services produced in primary, secondary and tertiary sector are included and the value of all intermediate transactions are ignored.

2. Value Added Approach I Value Added Method: To avoid double-counting, the value-added approach is used to estimate the National Income. According to this method, it is necessary to obtain the total of value-added at each stage in the manufacture of a commodity to arrive at Gross National Product. The value-added method can be explained by means of a simple example.

(a) In the above example, value of groundnut with shell is 50, after removing shells value of groundnut is 80, after crushing groundnut the value is 120 and when oil is packed in the packets its value is 150.
To avoid double-counting either the value of final output or the value – added should be taken in estimation of National Income.

The output method is widely used in the underdeveloped countries. In India, this method is applied in agriculture, mining and manufacturing sector.

Precautions:

• Avoid Double Counting: The value of only final goods and services must be considered and not the value of raw – materials or intermediary goods, etc.
• Self Consumption Goods: Goods used for self-consumption by farmers should be included in National Income.
• Price Level Changes to be considered: The values of national output must be expressed in terms of prices in some base year to know the national output in real terms i.e. N.I. at constant price.
• Net Income from Abroad: Care should be taken to include net income from abroad in National Income.
• Depreciation: Depreciation of capital assets should be deducted from the value of gross investment during the year.
• Indirect Taxes and Subsidies: To get National Income, deduct the indirect tax from the market price and add subsidies.
• Second-Hand Goods: Sale and purchase of second-hand goods should be ignored as it is not a part of current production.