Chemistry

Polymers

Question:

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

Answer:

Yes, step growth polymers (nucleic acids, proteins and starch) are conden ¬sation polymers and they can be formed by the loss of simple molecule like water leading to the formation of high molecular mass polymers.

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Polymers

Q 1.

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

Q 2.

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

Q 3.

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

Q 4.

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 5.

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 6.

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

Q 8.

Identify the type of polymer given in the following figure.
ncert-exemplar-problems-class-12-chemistry-polymers-19

Q 9.

Match the polymers given in Column I with their chemical names given in Column II.
ncert-exemplar-problems-class-12-chemistry-polymers-26

Q 10.

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

Q 11.

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

Q 12.

Write the free radical mechanism for the polymerisation of ethene.

Q 13.

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 14.

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

Q 15.

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

Q 16.

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

Q 17.

What are polymers?

Q 18.

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.

Q 19.

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

Q 20.

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

Q 21.

How are polymers classified on the basis of structure?

Q 22.

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

Q 23.

Which of the following monomers form biodegradable polymers?
(a) 3-hydroxybutanoic acid +3-hydroxypentanoic acid
(b) Glycine + aminocaproic acid  
(c) Ethylene glycol + phthalic acid
(d) Caprolactam

Q 24.

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

Q 25.

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

Q 26.

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 27.

Discuss the main purpose of vulcanisation of rubber.

Q 28.

Which of the following polymer is biodegradable?
ncert-exemplar-problems-class-12-chemistry-polymers-2
ncert-exemplar-problems-class-12-chemistry-polymers-3

Q 29.

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 30.

Match the polymers given in Column I with their main applications given in Column II.
ncert-exemplar-problems-class-12-chemistry-polymers-28

Q 31.

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

Q 32.

A natural linear polymer of 2-methyl-l,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?

Q 33.

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

Q 34.

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

Q 35.

Can enzyme be called a polymer?

Q 36.

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

Q 37.

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

Q 38.

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

Q 39.

Arrange the following polymers in increasing order of their intermolecuiar forces.
(i) Nylon 6,6, Buna-S, Polythene
(ii) Nylon 6, Neoprene, Polyvinyl chloride

Q 40.

In the following questions, a statement of Assertion (A) followed by a statement of
Reason (R) is given. Choose the correct answer out of the following choices:
(a) Assertion and Reason both are correct statements but Reason is not the correct explanation of Assertion.
(b) Assertion and Reason both are correct statements and Reason is the correct explanation of Assertion.
(c) Both Assertion and Reason are false.
(d) Assertion is correct but Reason is false.
(e) Assertion is false but Reason is correct.

Assertion (A): Rayon is a semi-synthetic polymer and is taken as a better choice than cotton fabric.
Reason (R): Mechanical and aesthetic properties of cellulose can be improved by acetylation.

Q 41.

What are natural and synthetic polymers? Give two examples of each type.

Q 42.

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

Q 43.

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

Q 44.

Explain the term copolymerisation and give two examples.

Q 45.

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

Q 46.

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

Q 47.

Match the polymers of Column I with correct monomers of Column II.
ncert-exemplar-problems-class-12-chemistry-polymers-25

Q 48.

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 49.

How does the presence of double bonds in rubber molecules influence their structure and reactivity?

Q 50.

How is dacron obtained from ethylene glycol and terephthalic acid?