Chemistry

Polymers

Question:

Assertion (A): Polyamides are best used as fibres because of high tensile strength.
Reason (R): 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.

Answer:

(b) Polyamides like nylons are best used fibres. They have high tensile strength due to presence of strong inter molecular hydrogen bond.

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Polymers

Q 1.

Is  (-NH — CHR—CO-)n a homopolymer or copolymer?

Q 2.

Write the monomers used for gettingThe following polymers:
(i) Polyvinylchloride
(ii) Teflon (iii) Bakelite

Q 3.

Which of the following polymers are used as fibre?
(a) Polytetrafluoroethane (b) Poly chloroprene
(c) Nylon (d) Terylene

Q 4.

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

Q 5.

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

Q 6.

What is a biodegradable polymer ? Give an example of a biodegradable aliphatic polyester.

Q 7.

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.

Q 8.

Assertion (A): Olefinic monomers undergo addition polymerization.
Reason (R): Polymerisation of vinyl chloride is initiated by peroxides/ persulphates.

Q 9.

Which of the following polymers are condensation polymers?
(a) Bakelite (b) Teflon
(c) Butyl rubber (d) Melamine formaldehyde resin

Q 10.

Which of the following are addition polymers?
(a) Nylon (b) Melamine formaldehyde resin
(c) Orion (d) Polystyrene

Q 11.

Out of chain growth polymerisation and step growth polymerisation, in which type will you place the following.
ncert-exemplar-problems-class-12-chemistry-polymers-18

Q 12.

Explain the difference between Buna- N and Buna-S.

Q 13.

Write the names and structures of the monomers of the following polymers:
(i) Buna-S (ii) Buna-N (iii) Dacron (iv) Neoprene

Q 14.


ncert-exemplar-problems-class-12-chemistry-polymers-7
ncert-exemplar-problems-class-12-chemistry-polymers-8

Q 15.

What is the role of benzoyl peroxide in addition polymerization of alkenes? Explain its mode of action with the help of an example.

Q 16.

What are polymers?

Q 17.

Write the free radical mechanism for the polymerisation of ethene.

Q 18.

Identify the monomer in the following polymeric structures:
ncert-solutions-for-class-12-chemistry-polymers-10

Q 19.

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

Q 20.

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

Q 21.

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?

Q 22.

Match materials given in Column I with the polymers given in Column II.
ncert-exemplar-problems-class-12-chemistry-polymers-31

Q 23.

In which classes, the polymers are classified on the basis of molecular forces?

Q 24.

Define thermoplastics and thermo setting polymers with two examples of each

Q 25.

What are the monomeric repeating units of Nylon-6 and Nylon 6,6?

Q 26.

How is the following resin intermediate prepared and which polymer is formed by this monomer unit?
ncert-exemplar-problems-class-12-chemistry-polymers-21

Q 27.

How are polymers classified on the basis of structure?

Q 28.

In which of the following polymers ethylene glycol is one of the monomer units?
ncert-exemplar-problems-class-12-chemistry-polymers-5

Q 29.

Assertion (A): Olefinic monomers undergo addition polymerization.
Reason (R): Polymerisation of vinyl chloride is initiated by peroxides/ persulphates.

Q 30.

Assertion (A): For making rubber synthetically, isoprene molecules are polymerised.
i Reason (R): Neoprene (a polymer of chloroprene) is a synthetic rubber.

Q 31.

Classify the following as addition and condensation polymers:
Terylene, Bakelite, Polyvinyl chloride,Polythene

Q 32.

Which of the following polymers, need at least one diene monomer for their preparation?
(a) Dacron (b) Buna-S (c) Neoprene (d) Novolac

Q 33.

Which of the following polymers are thermoplastic?
(a) Teflon (b) Natural rubber (c) Neoprene (d) Polystyrene

Q 34.

Which of the following are examples of synthetic rubber?
(a) Polychloroprene (b) Polyacrylonitrile
(c) Buna-N (d) cis-polyisoprene

Q 35.

Which of the following polymers have vinylic monomer units?
(a) Acrilan (b) Polystyrene (c) Nylon (d) Teflon

Q 36.

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?

Q 37.

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

Q 38.

Assertion (A): For making rubber synthetically, isoprene molecules are polymerised.
i Reason (R): Neoprene (a polymer of chloroprene) is a synthetic rubber.

Q 39.

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

Q 40.

Write the name and structure of one of the common initiators used in free radical addition polymerisation.

Q 41.

Discuss the main purpose of vulcanisation of rubber.

Q 42.

Explain the terms polymer and monomer.

Q 43.

Which of the following polymers can have strong intermolecular forces?
(a) Nylon (b) Polystyrene (c) Rubber (d) Polyester

Q 44.

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

Q 45.

Match the polymers given in Column I with the type of linkage present in them given in Column II.
ncert-exemplar-problems-class-12-chemistry-polymers-30

Q 46.

Assertion (A): Network polymers are thermosetting.
Reason (R): Network polymers have high molecular mass.

Q 47.

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

Q 48.

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

Q 49.

Define the term polymerisation?

Q 50.

How can you differentiate between addition and condensation polymerisatiop?