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NCERT Exemplar Class 12 Chemistry Solutions Chapter 15 Polymers

NCERT Exemplar Class 12 Chemistry Solutions Chapter 15 Polymers

Edited By Shivani Poonia | Updated on Jun 01, 2025 09:26 PM IST | #CBSE Class 12th
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CBSE Class 12th  Exam Date : 15 Jul' 2025 - 15 Jul' 2025

What made our daily lives convenient and much more colourful? Who played a significant role in many industries? "Polymers " provides a detailed explanation of monomers, types of polymers, application of polymers and the principles and theories that govern their behaviour. This chapter, Polymers, also deals with different types of polymers such as Natural And Synthetic Polymer, homopolymers and copolymers, Linear, Branched, and Cross-linked Polymers, Thermoplastics and Thermosets, addition and condensation polymers. The adaptability of polymers to different functions makes them indispensable in various industries, improving safety, convenience, and sustainability in our daily lives.

This Story also Contains
  1. NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: MCQ (Type 1)
  2. NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: MCQ (Type 2)
  3. NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Short Answer Type
  4. NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Matching Type
  5. NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Assertion and Reason Type
  6. Question:46
  7. NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Long Answer Type
  8. NCERT Class 12 Chemistry Chapter 15: Higher Order Thinking Skills (HOTS) Questions
  9. Approach to Solve Questions of Chapter 15 Polymers
  10. Major Topics Of NCERT Exemplar Class 12 Chemistry Chapter 15
  11. NCERT Exemplar Class 12 Chemistry Solutions
  12. Key Learning Of Class 12 Chemistry NCERT Exemplar Solutions Chapter 15
  13. NCERT Exemplar Class 12 Solutions
  14. NCERT Solutions for Class 12 Chemistry
  15. NCERT Solution subject wise
  16. NCERT Notes subject-wise
NCERT Exemplar Class 12 Chemistry Solutions Chapter 15 Polymers
NCERT Exemplar Class 12 Chemistry Solutions Chapter 15 Polymers

Our subject experts designed the NCERT Exemplar Solutions of Class 12 Chemistry Chapter 15 Polymers to offer a systematic and structured approach to these important concepts and help students to develop a clear understanding of critical concepts through the series of solved examples and conceptual explanations, these solutions provide a valuable resource to enhance performance in board exams as well as in the competitive exams like JEE Advanced, NEET, JEE Mains, etc. In this article, we will discuss detailed solutions to all the questions.


NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: MCQ (Type 1)

Question:1

Which of the following polymers of glucose is stored by animals?
(i) Cellulose
(ii) Amylose
(iii) Amylopectin
(iv) Glycogen

Answer:

The answer is the option (iv). Amongst the given options, glycogen is a polymer of glucose that is found in liver, brain and muscles of animals.

Question:2

Which of the following is not a semisynthetic polymer?
(i) cis-polyisoprene
(ii) Cellulose nitrate
(iii) Cellulose acetate
(iv) Vulcanised rubber

Answer:

The answer is the option (i). Of all the given options, Cis-polyisoprene is not a semisynthetic polymer. m-polyisoprene is a natural polymer while the others are semisynthetic polymers.

Question:3

The commercial name of polyacrylonitrile is ______________.
(i) Dacron
(ii) Orlon (Acrilan)
(iii) PVC
(iv) Bakelite

Answer:

The answer is the option (ii). The commercial name of polyacrylonitrile is Orion (acrilan). It is used as a substitute for wool in making commercial fibres.

Question:4

Which of the following polymer is biodegradable?

Answer:

The answer is the option (iii). PHBV is biodegradable in nature. It is formed by the copolymerisation of 3-hydroxybutanoic acid and 3-hydroxypentanoic acid.


Question:5

In which of the following polymers ethylene glycol is one of the monomer units?

Answer:

The answer is the option (i). The polymer given below is obtained on condensation polymerisation of ethylene glycol and phthalic acid. The water molecule gets eliminated in the process.

Question:6

Which of the following statements is not true about low-density polythene?
(i) Tough
(ii) Hard
(iii) Poor conductor of electricity
(iv) Highly branched structure

Answer:

The answer is the option (iii). We can obtain low-density polythene by polymerisation of ethane under high pressure. It tough but flexible (not too hard) in nature and has a highly branched structure.

Question:7


is a polymer having monomer units ____________.

Answer:

The answer is the option (i).

Question:8

Which of the following polymer can be formed by using the following monomer unit?

(i) Nylon 6, 6
(ii) Nylon 2–nylon 6
(iii) Melamine polymer
(iv) Nylon-6

Answer:

The answer is the option (iv). Nylon -6 is the polymer formed by heating caprolactam with water at a high temperature.


NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: MCQ (Type 2)

Question:9

Which of the following polymers, need at least one diene monomer for their preparation?
(i) Dacron
(ii) Buna-S
(iii) Neoprene
(iv) Novolac

Answer:

The answer is the option (ii, iii) Buna-S and neoprene need at least one diene monomer in their preparation. Buna-S is prepared by copolymerisation of 1, 3-butadiene and styrene in the presence of peroxide catalyst.

Neoprene is formed by the free radical polymerisation of chloroprene.

Question:10

Which of the following are characteristics of thermosetting polymers?
(i) Heavily branched cross-linked polymers.
(ii) Linear slightly branched long-chain molecules.
(iii) Become infusible on moulding so cannot be reused.
(iv) Soften on heating and harden on cooling, can be reused.

Answer:

The answer is the option (i, iii) Thermosetting polymers or thermoset are heavily branched and cross-linked molecules. They cannot be reused as they become infusible on the moulding.

Question:11

Which of the following polymers are thermoplastic?
(i) Teflon
(ii) Natural rubber
(iii) Neoprene
(iv) Polystyrene

Answer:

The answer is the option (i, iv) Thermoplastic polymers can be repeatedly softened on heating and hardened on cooling. Thus, they can be remoulded again and again. Teflon and polystyrene are common examples of thermoplastics.

Question:12

Which of the following polymers are used as fibre?
(i) Polytetrafluoroethane
(ii) Polychloroprene
(iii) Nylon
(iv) Terylene

Answer:

The answer is the option (iii, iv) Fibres have high tensile strength and modulus due to strong intermolecular forces like H-bonding. This leads to close packing in chain resulting in crystalline nature. Polyamides (Nylon) and Polyesters (terylene) are used as fibres.

Question:13

Which of the following are addition polymers?
(i) Nylon
(ii) Melamine formaldehyde resin
(iii) Orlon
(iv) Polystyrene

Answer:

The answer is the option (iii, iv) Orion and polystyrene are examples of addition polymers formed by repeated addition of monomer molecules. Orion is made by polymerisation of CH 2= CH - CN (acrylonitrile) and polystyrene by C6H5−CH=CH2(styrene)

Question:14

Which of the following polymers are condensation polymers?
(i) Bakelite
(ii) Teflon
(iii) Butyl rubber
(iv) Melamine formaldehyde resin

Answer:

The answer is the option (i, iv) Phenol when heated with formaldehyde gives an infusible solid mass known as bakelite. On condensation polymerisation of melamine and formaldehyde, melamine formaldehyde resin is obtained.

Question:15

Which of the following monomers form biodegradable polymers?
(i) 3-hydroxybutanoic acid + 3-hydroxypentanoic acid
(ii) Glycine + aminocaproic acid
(iii) Ethylene glycol + phthalic acid
(iv) Caprolactam

Answer:

The answer is the option (i, ii) The polymers which are easily decomposed are known as biodegradable polymer. PHBV is biodegradable in nature. It is formed by the copolymerisation of 3-hydroxybutanoic acid and 3-hydroxypentanoic acid. Glycine + amino caproic acid on copolymerisation give Nylon-2-nylon 6 which is also biodegradable.

Question:16

Which of the following is an example of a synthetic rubber?
(i) Polychloroprene
(ii) Polyacrylonitrile
(iii) Buna-N
(iv) cis-polyisoprene

Answer:

The answer is the option (i, iii)
Polychloroprene is a polymer of chloroprene and it is synthetic rubber.

Question:17

Which of the following polymers can have strong intermolecular forces?
(i) Nylon
(ii) Polystyrene
(iii) Rubber
(iv) Polyesters

Answer:

The answer is the option (i, iv). Polyamides (Nylon) and Polyesters (terylene) have high tensile strength and modulus due to strong intermolecular forces like H-bonding. This leads to close packing in the chain resulting in crystalline nature. That is why they are used as thread forming fibres.

Question:18

Which of the following polymers have vinylic monomer units?
(i) Acrilan
(ii) Polystyrene
(iii) Nylon
(iv) Teflon

Answer:

The answer is the option (i, ii, iv) Amongst the given options, acrilan, polystyrene and Teflon has vinylic
Monomer units.

Question:19

Vulcanisation makes rubber ______________.
(i) more elastic
(ii) soluble in inorganic solvent
(iii) crystalline
(iv) more stiff

Answer:

The answer is the option (i, iv). Vulcanisation is a chemical process wherein rubber is heated with Sulphur to form cross-links between rubber molecules. The process is carried to improve the physical properties like elasticity of natural rubber. It makes the rubber stiffer.

NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Short Answer Type

Question:20

A natural linear polymer of 2-methyl-1, 3-butadiene becomes hard on treatment with sulphur between 373 to 415 K and -S-S- bonds are formed between chains. Write the structure of the product of this treatment?

Answer:

The structures of the Vulcanised rubber molecules are as given below.

Question:21

Identify the type of polymer.
-A-A-A-A-A-A-

Answer:

Polymerisation of single monomeric species (one type of monomer unit) gives homopolymers. In this case the unit is A.

Question:22

Identify the type of polymer.
-A-B-B-A-A-A-B-A-

Answer:

Polymers wherein repeating structural unit has 2 types of monomer units (let’s say A and B) are known as copolymers.

Question:23

Out of chain growth polymerisation and step-growth polymerisation, in which type willyou place the following.

Answer:

It is a type of chain growth polymerisation because only addition occurs in this.

Question:24

Identify the type of polymer given in the following figure.

Answer:

The polymer given in the diagram is a cross linked polymer because a 3- D network structure (giant molecule) is formed from various polymer chains.

Question:25

Identify the polymer given below :

Answer:

The polymer given is cis-polyisoprene (natural rubber) and has a coiled structure. It shows elastic properties as well.

Question:26

Why are rubbers called elastomers?

Answer:

Rubber is a natural polymer with elastic properties, i.e. it stretches and relaxes with the application or removal of external force. That is why these are called elastomers.

Question:27

Can the enzyme be called a polymer?

Answer:

Since enzymes are biocatalysts that are basically proteins, they can be called polymers.

Question:28

Can nucleic acids, proteins and starch be considered as step growth polymers?

Answer:

Step growth polymers are formed by condensation polymerisation reaction resulting in the loss of simple molecule like water, alcohol that in turn, results in the formation of high molecular mass polymers. Nucleic acids, proteins and starch are formed in the same way. Hence, they can be considered as step-growth polymers.

Question:29

How is the following resin intermediate prepared and which polymer is formed by this monomer unit?

Answer:

The given intermediate is formed by the condensation polymerisation of melamine and formaldehyde. Its polymerisation gives melamine formaldehyde.

Question:30

To have practical applications, why are cross-links required in rubber?

Answer:

Cross-links are formed in the process of vulcanisation which is done to improve the physical properties of natural rubber. By cross-linking, rubber gets hard and tough due to increased tensile strength. The vulcanised rubber has higher elasticity, increased stiffness and low water absorption tendency.

Question:31

Why does cis-polyisoprene possess elastic property?

Answer:

The cis-polyisoprene molecule has a coiled structure. In it, several chains are held together by weak van der Waals interactions. This is why they possess elastic property.

Question:32

What is the structural difference between HDP and LDP? How does the structure account for different behaviour and nature, hence the use of a polymer?

Answer:

LDP or Low-density polythene has a highly branched molecular structure. It has low density (0.92 g/cm 3) and low melting point, as the molecules do not pack well due to branching. It is transparent and chemically inert with moderate toughness.
HDP or High-density polythene has linear chains, and thus the molecules are closely packed in space. Therefore, it has a higher density and melting point. In comparison to LDP, it is harder, tougher and has greater tensile strength.

Question:33

What is the role of benzoyl peroxide also polymerisation of alkenes? Explain its mode of action with the help of an example.

Answer:

The role of Benzoyl peroxide in free radical addition polymerisation of alkenes is to generate free radicals and act as an initiator of the reaction by providing chain initiation.

The free radical is added to the double bond of an alkene molecule forming the polymer.

The new free radical is added to a double bond of monomer to form a larger free radical, which when added to other alkene molecules forms the polymer.

Lastly chain termination step-

Question:34

Which factor imparts crystalline nature to a polymer like nylon?

Answer:

Polymers like nylon have strong intermolecular forces like hydrogen bonding that lead to close packing of polymer chains. This, along with the linear structure, gives a crystalline nature to the polymer.

Question:35

Name the polymers used in laminated sheets and give the name of monomeric units involved in its formation.

Answer:

The polymer is a urea-formaldehyde resin and the monomeric units are urea and formaldehyde.

Question:36

Which type of biomolecules has some structural similarity with synthetic polyamides? What is this similarity?

Answer:

The biomolecules having some structural similarity with synthetic polyamides are protein. The similarity is that the polyamides and proteins both contain amide linkage.

Question:37

Why should the monomers used in addition polymerisation through free radical pathway be very pure?

Answer:

The monomers used in addition polymerisation through free radical should be very pure because even a tiny amount of impurities may act as initiators leading to the formation of polymers with small chain lengths.

NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Matching Type

Question:38

Match the polymer of column I with a correct monomer of column II.

Column I
Column II
(i) High density polythene
(a) Isoprene
(ii) Neoprene
(b) Tetrafluoroethene
(iii) Natural rubber
(c) Chloroprene
(iv) Teflon
(d) Acrylonitrile
(v) Acrilan
(e) Ethene
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Answer:

(i → e), (ii → c), (iii →a), (iv → b), (v →d)

Question:39

Match the polymers given in Column I with their chemical names given in Column II.

Column I
Column II
(i) Nylon 6
(a) Polyvinyl chloride
(ii) PVC
(b) Polyacrylonitrile
(iii) Acrilan
(c) Polycaprolactum
(iv) Natural rubber
(d) Low density Polythene
(v) LDP
(e) cis-polyisoprene

Answer:

(i → c), (ii → a), (iii → b), (iv → e), (v → d)

Question:40

Match the polymers given in Column I with their commercial names given in Column II.

Column I
Column II
(i) The polyester of glycol and phthalic acid
(a) Novolac
(ii) The copolymer of 1, 3-butadiene and styrene
(b) Glyptal
(iii) Phenol and formaldehyde resin
(c) Buna-S
(iv) The polyester of glycol and terephthalic acid
(d) Buna -N
(v) The copolymer of 1, 3-butadiene and acrylonitrile
(e) Dacron

Answer:

(i → b), (ii → c), (iii → a), (iv → e), (v → d)

Question:41

Match the polymers given in Column I with their main applications given in Column II.

Column I
Column II
i) Bakelite
(a) Unbreakable crockery
ii) Low-density polythene
(b) Non-stick cookwares
iii) Melamine-formaldehyde resin
(c) Packaging material for shock absorbance
iv) Nylon 6
(d) Electrical switches
v) Polytetrafluoroethane
(e) Squeeze bottles
vi) Polystyrene
(f) Tyre, cords

Answer:

(i → d), (ii → e), (iii → a), (iv → f), (v → b), (vi → c)

Question:42

Match the polymers given in Column I with the preferred mode of polymerisation followed by their monomers.

Column I
Column II
(i) Nylon -6,6
(a) Free radical polymerisation
(ii) PVC
(b) Ziegler-Natta polymerisation or Co-ordination polymerisation
(iii) HDP
(c) Anionic Polymerisation

(d) Condensation polymerisation

Answer:

(i → d), (ii → a), (iii → b)

Question:43

Match the polymers given in Column I with the type of linkage present in they have given in Column II.

Column I
Column II
(i) Terylene
(a) Glycosidic linkage
(ii) Nylon
(b) Ester linkage
(iii) Cellulose
(c) Phosphodiester linkage
(iv) Protein
(d) Amide linkage
(v) RNA

Answer:

(i → b), (ii → d), (iii → a), (iv → d), (v → c)

Question:44

Match materials are given in Column I with the polymers given in Column II.

Column I
Column II
(i) Natural rubber latex
(a) Nylon
(ii) Wood laminates
(b) Neoprene
(iii) Ropes and fibres
(c) Dacron
(iv) Polyester fabric
(d) Melamine formaldehyde resins
(v) Synthetic rubber
(e) Urea-formaldehyde resins
(vi) Unbreakable crockery
(f) cis-polyisoprene

Answer:

(i → f), (ii → e), (iii → a), (iv → c), (v → b), (vi → d)

Question:45

Match the polymers given in Column I with their repeating units given in Column II

Column I
Column II
(i) Acrilan
(a)
(ii) Polystyrene
(b)
(iii) Neoprene
(c)
(iv) Novolac
(d)
(v) Buna-N
(e)

(f)

Answer:

(i → d), (ii → a), (iii → b), (iv → e),(v → c)

NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Assertion and Reason Type

Question:46

In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Rayon is a semi-synthetic polymer and is taken as a better choice than cotton fabric.
Reason: Mechanical and aesthetic properties of cellulose can be improved by acetylation.
(i) Assertion and reason both are correct statements, but reason does not explain the assertion.
(ii) Assertion and reason both are correct statements, and reason explain the assertion.
(iii) Both assertion and reason are the wrong statements.
(iv) The assertion is correct statement and reason is the wrong statement.
(v) The assertion is the wrong statement and reason is the correct statement.

Answer:

The answer is the option (ii). Rayon is semi-synthetic polymer and is taken as a better choice than cotton fabric because mechanical and aesthetic properties of cellulose can be improved by acetylation. Thus, both assertion and reason are correct with the latter being the correct explanation.

Question:47

In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Most of the Synthetic polymers are not biodegradable.
Reason: Polymerisation process induces toxic character in organic molecules.
(i) Assertion and reason both are correct statements, but reason does not explain the assertion.
(ii) Assertion and reason both are correct statements, and reason explain the assertion.
(iii) Both assertion and reason are the wrong statements.
(iv) The assertion is correct statement and reason is the wrong statement.
(v) The assertion is the wrong statement and reason is the correct statement.

Answer:

The answer is the option (iv). Most of the synthetic polymers are non-biodegradable in nature i.e. they are not degraded by enzymatic, hydrolytic and environmental oxidation. Polymerisation process does not induce toxic characters in organic molecules.

Question:48

In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Olefinic monomers undergo addition polymerisation.
Reason: Polymerisation of vinyl chloride is initiated by peroxides/persulphates.
(i) Assertion and reason both are correct statements, but reason does not explain the assertion.
(ii) Assertion and reason both are correct statements, and reason explain the assertion.
(iii) Both assertion and reason are the wrong statements.
(iv) The assertion is correct statement and reason is the wrong statement.
(v) The assertion is the wrong statement and reason is the correct statement.

Answer:

The answer is the option (i). Olefinic monomers like ethene undergo addition polymerisation. The monomers used in addition polymerisation reaction are unsaturated compounds like alkenes, alkadienes etc. The assertion and reason both are correct statements but the reason does not explain the assertion.

Question:49

In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Polyamides are best used as fibres because of high tensile strength.
Reason: Strong intermolecular forces (like hydrogen bonding within polyamides) lead to close packing of chains and increase the crystalline character, hence, provide high tensile strength to polymers.
(i) Assertion and reason both are correct statements, but reason does not explain the assertion.
(ii) Assertion and reason both are correct statements, and reason explain the assertion.
(iii) Both assertion and reason are the wrong statements.
(iv) The assertion is correct statement and reason is the wrong statement.
(v) The assertion is the wrong statement and reason is the correct statement.

Answer:

The answer is the option (ii). Polyamides are best-used fibers because they have high tensile strength. They have closely packed chains and increased crystalline character due to presence of strong inter molecular forces like hydrogen bonding.

Question:50

In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: For making rubber synthetically, isoprene molecules are polymerised.
Reason: Neoprene (a polymer of chloroprene) is a synthetic rubber.
(i) Assertion and reason both are correct statements, but reason does not explain the assertion.
(ii) Assertion and reason both are correct statements, and reason explain the assertion.
(iii) Both assertion and reason are the wrong statements.
(iv) The assertion is correct statement and reason is the wrong statement.
(v) The assertion is the wrong statement and reason is the correct statement.

Answer:

(v) Isoprene (2-methyl-1,3-butadiene) molecule is the monomer for natural rubber. Neoprene (a polymer of chloroprene) is a synthetic rubber.

Question:51

In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Network polymers are thermosetting.
Reason: Network polymers have high molecular mass.
(i) Assertion and reason both are correct statements, but reason does not explain the assertion.
(ii) Assertion and reason both are correct statements, and reason explain the assertion.
(iii) Both assertion and reason are the wrong statements.
(iv) The assertion is correct statement and reason is the wrong statement.
(v) The assertion is the wrong statement and reason is the correct statement.

Answer:

The answer is the option (i). Network polymers are thermosetting and have high molecular mass. However, the reason they are thermosetting is because of extensive cross-linking during polymerisation and not because of higher molecular mass.

Question:52

In the following question a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Polytetrafluoroethene is used in making non-stick cookware.
Reason: Fluorine has the highest electronegativity.
(i) Assertion and reason both are correct statements, but reason does not explain the assertion.
(ii) Assertion and reason both are correct statements, and reason explain the assertion.
(iii) Both assertion and reason are the wrong statements.
(iv) The assertion is correct statement and reason is the wrong statement.
(v) The assertion is the wrong statement and reason is the correct statement.

Answer:

The answer is the option (i). Polytetrafluoroethene or Teflon is used in making nonstick cookware, as it is chemically inert, resistant to attack by corrosive reagents and thermally stable.

NCERT Exemplar Class 12 Chemistry Solutions Chapter 1: Long Answer Type

Question:53

Synthetic polymers do not degrade in the environment for a long time. How can biodegradable synthetic polymers be made. Differentiate between biopolymers and biodegradable polymers and give examples of each type.

Answer:

Synthetic polymers are non-biodegradable as they are resistant to environmental degradation process. They form a major share of the polymer solid waste material.
Biopolymers are natural polymers of amino acids or carbohydrates, linked together by peptide or glycosidic linkages. They are found in plants and animals.

Biopolymer may or may not be biodegradable. For example: while protein and starch are biodegradable, keratin is not. Biodegradable polymer is polymers which are not resistant to environmental degradation process, e.g., DHBV nylon-2, nylon-6. Both the biodegradable polymers and biopolymers contain similar functional group.

Question:54

Differentiate between rubbers and plastics on the basis of intermolecular forces.

Answer:

Rubber
Plastics
The molecule consists of chains held together by weak Van Der Waals interaction.
Intermolecular forces of attarction intermediate between elastomers and fibre.
Coiled structure
Linear or slightly branched long chain
Returns to its original shape, size and length after being stretched.
Not really elastic in nature but capable of softening on heating and hardening on cooling.

Question:55

Phenol and formaldehyde undergo condensation to give a polymar (A) which on heating with formaldehyde gives a thermosetting polymer (B). Name the polymers. Write the reactions involved in the formation of (A). What is the structural difference between two polymers?

Answer:

Polymer ‘A’ in the question is Novalac and ‘B’ is bakelite. The reactions involved are:

The main structural difference between them is that novolac is a linear chain polymer while bakelite is a cross-linked polymer.

Question:56

Low-density polythene and high-density polythene, both are polymers of ethane, but there is marked difference in their properties. Explain.

Answer:

LDP
HDP
Formed at a temperature of 350 K to 570 K and very high pressure of about 1000-2000 atm.
The temperature of about 333 K to 343 K and a pressure of 6-7 atm is required.
It is obtained by free-radical addition and has a highly branched structure.
It has straight linear molecules and a high density.
Chemically inert and tough but flexible.
Chemically inert.
Tougher and harder than LDP

Question:57

Which of the following polymers soften on heating and harden on cooling? What are the polymers with this property collectively called? What are the polymers with this property collectively called? What are the structural similarities between such polymers? Bakelite, urea-formaldehyde resin, polythene, polyvinyl, polystyrene.

Answer:

Thermoplastic polymers soften on heating and harden on cooling. Polythene, polyvinyl and polystyrene are thermoplastic polymers. Their intermolecular force of attraction is somewhere between elastomers and fibres. They soften on heating and harden on cooling.
Bakelite, urea-formaldehyde resin are examples of thermosetting polymers. They are cross-linked and cannot be reused.

NCERT Class 12 Chemistry Chapter 15: Higher Order Thinking Skills (HOTS) Questions

Question 1: Given below are two statements:
Statement I: Wet cotton clothes made of cellulose based carbohydrate takes comparatively longer time to get dried than wet nylon polymer-based clothes.

Statement II: Intermolecular hydrogen bonding with water molecule is more in nylon-based clothes than in the case of cotton clothes.

In the light of above statements, choose the Correct answer from the options given below

(1) Statement I is false but Statement II is true

(2) Statement I is true but Statement II is false

(3) Both Statement I and Statement II are true

(4) Both Statement I and Statement II are false

Answer: Wet cellulose-based cotton clothes take more time to dry than wet nylon-based clothes due to the greater number of H-bonds between cellulose and water molecules.

So, Statement I is correct

Statement II is incorrect.

Hence, the correct answer is option (2).

Question 2: Which of the following polymers are used as fibre?

(i) Polytetrafluoroethylene

(ii) Polychloroprene

(iii) Nylon

(iv) Terylene

Options

(1) (i) and (ii)

(2) (iii) and (iv)

(3) (ii) and (iii)

(4) (i) and (iv)

Answer: Fibres have high tensile strength and modulus due to strong intermolecular forces like H-bonding. This leads to close packing in chains, resulting in crystalline nature. Polyamides (Nylon) and Polyesters (terylene) are used as fibres.

Hence, the answer is the option (2).

Approach to Solve Questions of Chapter 15 Polymers

The approach to solve the questions must be simple yet effective. Following are some points that can help you building up the strategy
1. Understand the Basic Concepts of polymers

  • Classification of Polymers
  • Classification based on structure, sources and mode of polymerisation
  • Difference between synthetic and natural polymers
  • Uses and properties of some important polymers
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2. Memorise the names of monomers and polymers

  • Important polymers like PVC, Teflon, Nylon-6,6, Bakelite are important and used often.

3. Practice of reaction mechanism

  • Understand the reactions
  • Practice writing polymerisation reactions
  • Addition and condensation processes are important

4. Some differences are important to memorise

  • Thermoplastic vs Thermosetting
  • Addition polymerisation vs condensation polymerisation

5. Solve NCERT questions and Examples

  • NCERT questions are asked directly in exams like CBSE and state boards
  • Questions in competitive exams like NEET, JEE are asked directly from the NCERT

6. While solving questions that include structures of monomers and polymers, it will help students an extra edge.

7. Revise again and again to memorise concepts and structures.

Major Topics Of NCERT Exemplar Class 12 Chemistry Chapter 15

  • Classification of Polymers
  • Classification Based on Source
  • Classification Based on Structure of Polymers
  • Classification Based on Mode of Polymerisation
  • Classification Based on Molecular Forces
  • Classification Based on Growth Polymerisation
  • Types of Polymerisation Reactions
  • Addition Polymerisation or Chain Growth Polymerisation
  • Condensation Polymerisation or Step Growth polymerization
  • Copolymerisation
  • Rubber
  • Molecular Mass of Polymers
  • Biodegradable Polymers
  • Polymers of Commercial Importance

NCERT Exemplar Class 12 Chemistry Solutions

NCERT Exemplar Class 12 Chemistry Chapter 1 Solid State

NCERT Exemplar Class 12 Chemistry Chapter 2 Solutions

NCERT Exemplar Class 12 Chemistry Chapter 3 Electrochemistry

NCERT Exemplar Class 12 Chemistry Chapter 4 Chemical Kinetics

NCERT Exemplar Class 12 Chemistry Chapter 5 Surface Chemistry

NCERT Exemplar Class 12 Chemistry Chapter 6 General Principles and Processes of Isolation of Elements

NCERT Exemplar Class 12 Chemistry Chapter 7 The p-Block Elements

NCERT Exemplar Class 12 Chemistry Chapter 8 The d & f Block Elements

NCERT Exemplar Class 12 Chemistry Chapter 9 Coordination Compounds

NCERT Exemplar Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes

NCERT Exemplar Class 12 Chemistry Chapter 11 Alcohols, Phenols, and Ethers

NCERT Exemplar Class 12 Chemistry Chapter 12 Aldehydes, Ketones, and Carboxylic Acids

NCERT Exemplar Class 12 Chemistry Chapter 13 Amines

NCERT Exemplar Class 12 Chemistry Chapter 14 Biomolecules

NCERT Exemplar Class 12 Chemistry Chapter 15 Polymers

NCERT Exemplar Class 12 Chemistry Chapter 16 Chemistry in Everyday Life


Key Learning Of Class 12 Chemistry NCERT Exemplar Solutions Chapter 15

NCERT Exemplar Class 12 Chemistry chapter 15 solutions Polymers have a diverse range of industrial and commercial uses. Industries like automotive, aerospace, electronics, packaging, and medical use polymers' adaptability and flexibility. They are used in drug delivery, biometric sensors, genetic engineering, aerospace engineering, and cosmetics.

They have been used in sports, molecular recognition, water purification, biopolymers to save the environment, bulletproof vests, fire resistance, holography, renewable biomass applications, and 3D printing.

Without polymers, our lives would not have been so easy going and fast. From plastic packaging to huge rocket structures, polymers have always been the backbone of many major industries.

NCERT Exemplar Class 12 Solutions


NCERT Solutions for Class 12 Chemistry

NCERT solutions for class 12 Chemistry chapter 1 Solutions

NCERT Solutions for class 12 Chemistry chapter 2 Electrochemistry

NCERT solutions for class 12 Chemistry chapter 3 Chemical Kinetics

NCERT solutions for class 12 Chemistry chapter 4 The d and f block elements

NCERT solutions for class 12 Chemistry chapter 5 Coordination compounds

NCERT Solutions for class 12 Chemistry chapter 6 Haloalkanes and Haloarenes

NCERT solutions for class 12 Chemistry chapter 7 Alcohols, Phenols, and Ethers

NCERT Solutions for class 12 Chemistry chapter 8 Aldehydes, Ketones and Carboxylic Acids

NCERT solutions for class 12 Chemistry chapter 9 Amines

NCERT solutions for class 12 Chemistry chapter 10 Biomolecules

NCERT Solution subject wise

NCERT Notes subject-wise


NCERT Notes for Class 12 Physics
NCERT Notes for Class 12 Chemistry
NCERT Notes for Class 12 Maths
NCERT Notes for Class 12 Biology


Check NCERT Books and NCERT Syllabus

Frequently Asked Questions (FAQs)

1. What are polymers, and how are they classified?

Polymers are large molecules made up of repeating structural units called monomers, which are covalently bonded. They can be classified based on several criteria:   
1. Nature of Monomers: Homopolymers (made from one type of monomer) and copolymers (made from two or more types of monomers).  
2. Structure: Linear, branched, or cross-linked polymers.  
3. Source: Natural polymers (like proteins and cellulose) and synthetic polymers (like nylon and polyester).  
4. Thermal behavior: Thermoplastics (which can be melted and reshaped) and thermosetting polymers (which do not melt on reheating).

2. What is the significance of the degree of polymerization in polymers?

The degree of polymerization (DP) refers to the number of repeating monomer units in a polymer chain. It significantly affects the properties of the polymer, including its molecular weight, mechanical strength, and thermal stability. Higher DP typically leads to stronger and more durable materials, whereas lower DP may result in more flexible and less resilient polymers. Understanding DP helps in tailoring polymers for specific applications

3. How does the process of polymerization occur?

Polymerization can occur through various mechanisms, primarily addition, chain growth and condensation, step growth.  
1. Addition Polymerization: Involves the addition of unsaturated monomers (like alkenes) without the loss of any small molecules. Initiators, heat, or light are often required to start the process.
2. Condensation Polymerization: Involves two different monomers that react to form a polymer while releasing small molecules like water. This method includes the formation of polyesters and polyamides.
Both processes are essential for creating diverse polymers used in various applications.

4. What are some common applications of polymers in our daily lives?

 Polymers play a crucial role in numerous applications, greatly impacting our daily lives. Some common uses include:  

  • Packaging Materials: Such as polyethylene and polypropylene, used in bags and containers.  
  • Textiles: Fibers like nylon, polyester, and spandex used in clothing.  
  • Automotive Parts: Components made from reinforced plastics to reduce weight and increase fuel efficiency.  
  • Biomedical Devices: Such as implants and drug delivery systems made from biocompatible polymers.  
    These examples illustrate how versatile and essential polymers are across various industries.
5. What factors influence the properties of a polymer?

Several factors influence the properties of a polymer, including:  
1. Chemical Structure: The type of monomers and their arrangement can affect rigidity, elasticity, and thermal behavior.  
2. Degree of Polymerization: As mentioned earlier, higher DP generally leads to increased strength and stability.  
3. Cross-linking: The extent and nature of cross-linking between polymer chains can affect flexibility and durability.  
4. Additives: Plasticizers, stabilizers, and other additives can modify properties to enhance performance for specific applications.  
Understanding these factors helps in developing polymers tailored to meet specific needs and challenges in various fields.

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Questions related to CBSE Class 12th

Have a question related to CBSE Class 12th ?
Can I change my board from CBSE to CHSE Odisha in Class 12th?

Changing from the CBSE board to the Odisha CHSE in Class 12 is generally difficult and often not ideal due to differences in syllabi and examination structures. Most boards, including Odisha CHSE , do not recommend switching in the final year of schooling. It is crucial to consult both CBSE and Odisha CHSE authorities for specific policies, but making such a change earlier is advisable to prevent academic complications.

Read Complete Answer
Manasvini Gupta 30 January,2025
quartely question paper for mathematics cbse

Hello there! Thanks for reaching out to us at Careers360.

Ah, you're looking for CBSE quarterly question papers for mathematics, right? Those can be super helpful for exam prep.

Unfortunately, CBSE doesn't officially release quarterly papers - they mainly put out sample papers and previous years' board exam papers. But don't worry, there are still some good options to help you practice!

Have you checked out the CBSE sample papers on their official website? Those are usually pretty close to the actual exam format. You could also look into previous years' board exam papers - they're great for getting a feel for the types of questions that might come up.

If you're after more practice material, some textbook publishers release their own mock papers which can be useful too.

Let me know if you need any other tips for your math prep. Good luck with your studies!

Read Complete Answer
Jefferson 25 September,2024
i have taken admission in clg after my campartment exam in chemistry along with the neet 2025 preperation but unfortunately i again got campartment after doing all this preparation i got 15 marks only now I can't able to think what should I do next.

It's understandable to feel disheartened after facing a compartment exam, especially when you've invested significant effort. However, it's important to remember that setbacks are a part of life, and they can be opportunities for growth.

Possible steps:

  1. Re-evaluate Your Study Strategies:

    • Identify Weak Areas: Pinpoint the specific topics or concepts that caused difficulties.
    • Seek Clarification: Reach out to teachers, tutors, or online resources for additional explanations.
    • Practice Regularly: Consistent practice is key to mastering chemistry.

  2. Consider Professional Help:

    • Tutoring: A tutor can provide personalized guidance and support.
    • Counseling: If you're feeling overwhelmed or unsure about your path, counseling can help.

  3. Explore Alternative Options:

    • Retake the Exam: If you're confident in your ability to improve, consider retaking the chemistry compartment exam.
    • Change Course: If you're not interested in pursuing chemistry further, explore other academic options that align with your interests.

  4. Focus on NEET 2025 Preparation:

    • Stay Dedicated: Continue your NEET preparation with renewed determination.
    • Utilize Resources: Make use of study materials, online courses, and mock tests.

  5. Seek Support:

    • Talk to Friends and Family: Sharing your feelings can provide comfort and encouragement.
    • Join Study Groups: Collaborating with peers can create a supportive learning environment.

Remember: This is a temporary setback. With the right approach and perseverance, you can overcome this challenge and achieve your goals.

I hope this information helps you.







Read Complete Answer
Kanishka kaushikii 17 September,2024
i scored 84 percent in cbse 2 years ago.Am i eligible for medhavi scholarship if give 12th again after 2 drop years and will got 75+ in mpboard

Hi,

Qualifications:
Age: As of the last registration date, you must be between the ages of 16 and 40.
Qualification: You must have graduated from an accredited board or at least passed the tenth grade. Higher qualifications are also accepted, such as a diploma, postgraduate degree, graduation, or 11th or 12th grade.
How to Apply:
Get the Medhavi app by visiting the Google Play Store.
Register: In the app, create an account.
Examine Notification: Examine the comprehensive notification on the scholarship examination.
Sign up to Take the Test: Finish the app's registration process.
Examine: The Medhavi app allows you to take the exam from the comfort of your home.
Get Results: In just two days, the results are made public.
Verification of Documents: Provide the required paperwork and bank account information for validation.
Get Scholarship: Following a successful verification process, the scholarship will be given. You need to have at least passed the 10th grade/matriculation scholarship amount will be transferred directly to your bank account.

Scholarship Details:

Type A: For candidates scoring 60% or above in the exam.

Type B: For candidates scoring between 50% and 60%.

Type C: For candidates scoring between 40% and 50%.

Cash Scholarship:

Scholarships can range from Rs. 2,000 to Rs. 18,000 per month, depending on the marks obtained and the type of scholarship exam (SAKSHAM, SWABHIMAN, SAMADHAN, etc.).

Since you already have a 12th grade qualification with 84%, you meet the qualification criteria and are eligible to apply for the Medhavi Scholarship exam. Make sure to prepare well for the exam to maximize your chances of receiving a higher scholarship.

Hope you find this useful!

Read Complete Answer
Yuvan 30 August,2024
i upload 12th board result screenshot in ncweb form from the cbse site so it is valid

hello mahima,

If you have uploaded screenshot of your 12th board result taken from CBSE official website,there won,t be a problem with that.If the screenshot that you have uploaded is clear and legible. It should display your name, roll number, marks obtained, and any other relevant details in a readable forma.ALSO, the screenshot clearly show it is from the official CBSE results portal.

hope this helps.

Read Complete Answer
Ashvadha 12 July,2024
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Popular CBSE Class 12th Questions

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

 Option 2)

0.16\; J
Option 3)

1.00\; J

 Option 4)

0.67\; J
Read More

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

 Option 2)

 6.45×10−3 kg
Option 3)

 9.89×10−3 kg

 Option 4)

12.89×10−3 kg

 
Read More

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

 Option 2)

200 \, \, J - 500 \, \, J
Option 3)

2\times 10^{5}J-3\times 10^{5}J

 Option 4)

20,000 \, \, J - 50,000 \, \, J
Read More

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

 Option 2)

\; K\;
Option 3)

zero\;

 Option 4)

K/4
Read More

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

 Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced
Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

 Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .
Read More

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

 Option 2)

3.125 × 10-2
Option 3)

1.25 × 10-2

 Option 4)

2.5 × 10-2
Read More

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

 Option 2)

increase two fold
Option 3)

remain unchanged

 Option 4)

be a function of the molecular mass of the substance.
Read More

With increase of temperature, which of these changes?

Option 1)

Molality

 Option 2)

Weight fraction of solute
Option 3)

Fraction of solute present in water

 Option 4)

Mole fraction.
Read More

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

 Option 2)

6.023 × 1022
Option 3)

half that in 8 g He

 Option 4)

558.5 × 6.023 × 1023
Read More

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

 Option 2)

more than 3 but less than 6
Option 3)

more than 6 but less than 9

 Option 4)

more than 9
Read More

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CBSE supplementary exams 2025 from July 15; form submission starts on May 30
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