Polymers - MCQs with Explanations

1. Nylon-6 as compared to nylon 6,6 has lower:

• (a) abrasion resistance
• (b) thermal stability
• (c) adhesion to rubber
• (d) hardness.

Correct Answer: (a)

Explanation: Nylon 6,6 is known for its high tenacity, elasticity, and remarkable resistance to abrasion, which are superior to those of Nylon-6.

2. Phosphates (e.g., tricresyl, tributyl, triphenyl etc.) are added to polymers to act as:

• (a) hardeners
• (b) anti-shrinkage agents
• (c) plasticisers
• (d) transparency improver.

Correct Answer: (c)

Explanation: Organophosphates are widely used as plasticisers or dispersants; these are additives that increase the plasticity or fluidity of polymers.

3. Which of the following is the most important rubber compounding ingredient which is used to improve wearing qualities of both natural rubber and SBR by imparting toughness?

• (a) Phosphorous
• (b) Carbon black
• (c) Pine oil
• (d) Rosin

Correct Answer: (b)

Explanation: Carbon black is the most widely used material to provide adequate tensile properties, abrasion resistance, or tear strength to rubber.

4. Which one of the following statements is not true?

• (a) Natural rubber has the trans-configuration at every double bond.
• (b) Buna-S is a copolymer of butadiene and styrene.
• (c) Natural rubber is a 1,4-polymer of isoprene.
• (d) In vulcanisation, the formation of sulphur bridges between different chains make rubber harder and stronger.

Correct Answer: (a)

Explanation: Natural rubber is actually cis-1,4-polyisoprene; the repeating units have the cis-configuration, which is essential for its elasticity.

5. Rayon is superior to cotton in making gauge for wound treatment because:

• (a) rayon is a synthetic polymer
• (b) rayon does not stick to the wound unlike cotton
• (c) rayon can absorb over 90% of its own weight of water
• (d) both (b) and (c).

Correct Answer: (b)

Explanation: Rayon is preferred for wound treatment primarily because it does not stick to the wound, making it superior to cotton in this specific application.

6. Perspex can be used as a substitute of glass. Its monomer is:

• (a) methyl methacrylate
• (b) DMT
• (c) butadiene
• (d) tetrafluoroethylene.

Correct Answer: (a)

Explanation: Perspex (also known as Plexiglas or Lucite) is a synthetic polymer made from the monomer methyl methacrylate.

7. Among cellulose, polyvinyl chloride, nylon and natural rubber, the polymer in which the intermolecular force of attraction is weakest, is:

• (a) nylon
• (b) polyvinyl chloride
• (c) cellulose
• (d) natural rubber.

Correct Answer: (d)

Explanation: Natural rubber belongs to the class of elastomers, which possess the weakest intermolecular (van der Waals) forces of attraction.

8. Addition of stabilizer during PVC manufacture is done to:

• (a) improve its impact strength
• (b) improve its elasticity
• (c) reduce the melt viscosity
• (d) prevent its thermal degradation.

Correct Answer: (d)

Explanation: PVC degrades at elevated temperatures by releasing HCl, which further accelerates the process. Thermal stabilizers are added to prevent this degradation.

9. Flexible foam (for mattresses) are usually made of:

• (a) PVC
• (b) silicone rubber
• (c) polyurethanes
• (d) polyamides.

Correct Answer: (c)

Explanation: Polyurethanes are commonly used in the manufacture of flexible and high-resilience foams used for mattresses.

10. Pick out the wrong statement:

• (a) Linear polymers are thermoplastics.
• (b) Cross-linked polymers are either elastomeric or thermosetting.
• (c) Branching in cross-linked polymers reduces solubility and increases softening point.
• (d) Dibasic acids reacts with dihydric alcohols to give polyesters using addition polymerisation reaction.

Correct Answer: (d)

Explanation: Polyesters are formed through condensation polymerisation, not addition polymerisation.

11. Which of the following is an antioxidant used in rubber?

• (a) Carbon
• (b) Alkylated diphenylamine
• (c) Thiokol
• (d) Magnesium

Correct Answer: (b)

Explanation: Alkylated diphenylamine is a common example of a staining antioxidant used to protect rubber from light, heat, and ozone.

12. The number average molar mass and mass average molar mass of a polymer are 30,000 and 40,000. The polydispersity index is:

• (a) < 1
• (b) > 1
• (c) 0
• (d) -1

Correct Answer: (b)

Explanation: P.D.I = Mass average molar mass / Number average molar mass. Here, $40,000 / 30,000 = 1.33$, which is greater than 1.

13. Buna-N synthetic rubber is a co-polymer of:

• (a) Chloroprene and 1,3-butadiene
• (b) 1,3-butadiene and styrene
• (c) 1,3-butadiene and acrylonitrile
• (d) Vinyl cyanide and chloroprene.

Correct Answer: (c)

Explanation: Buna-N is formed by the copolymerisation of 1,3-butadiene and acrylonitrile (vinyl cyanide) in the presence of a peroxide catalyst.

14. The polymer containing strong intermolecular forces e.g., hydrogen bonding is:

• (a) natural rubber
• (b) teflon
• (c) nylon-6,6
• (d) polystyrene.

Correct Answer: (c)

Explanation: Nylon-6,6 contains amide linkages ($-CONH-$), which allow for very strong intermolecular hydrogen bonding between polyamide chains.

15. Polymerisation of propene using Ziegler-Natta catalyst is advantageous over free radical polymerisation because:

• (a) it can lead to living polymers
• (b) it results in a highly cross-linked polymer
• (c) it gives highly branched polymer
• (d) it gives linear polymer molecules permitting stereochemical control.

Correct Answer: (d)

Explanation: Ziegler-Natta catalysts produce linear, stereoregular polymers (like isotactic polypropylene), providing much better control over the polymer structure than free radical methods.

16. Although styrene undergoes both cationic and anionic polymerisation, one method is always preferred with substituted styrenes. Which method is preferred with $-NO_{2}$ substituted styrene?

• (a) Radical polymerisation
• (b) Cationic polymerisation
• (c) Anionic polymerisation
• (d) None of the above.

Correct Answer: (c)

Explanation: The nitro group is strongly electron-withdrawing, which stabilizes the intermediate carbanion, making anionic polymerisation the preferred method.

17. The given polymer structure [cis-isoprene] is:

• (a) natural rubber
• (b) gutta percha
• (c) neoprene
• (d) polypropylene.

Correct Answer: (a)

Explanation: The cis-isomer of polyisoprene is natural rubber. Its trans-isomer is known as gutta percha.

18. Which of the following is a condensation polymer?

• (a) Nylon-6
• (b) Natural Rubber
• (c) Polyvinyl chloride
• (d) Polyethylene.

Correct Answer: (a)

Explanation: Nylon-6 is a polyamide formed by the condensation polymerisation of caprolactam. The others are addition polymers.

19. A polymer formed by coordination polymerisation is:

• (a) low density polythene
• (b) high density polythene
• (c) Nylon-6
• (d) dacron.

Correct Answer: (b)

Explanation: High density polythene (HDPE) is manufactured using coordination polymerization with Ziegler-Natta catalysts.

20. Which of the following is wrong?

• (a) PMMA is called plexiglass.
• (b) PTFE is called teflon.
• (c) SBR is natural rubber.
• (d) LDPE is low density polythene.

Correct Answer: (c)

Explanation: SBR (Styrene-Butadiene Rubber) is a synthetic rubber (Buna-S), whereas natural rubber is cis-polyisoprene.

21. Novolac is:

• (a) linear condensation product of phenol and formaldehyde
• (b) cross linked product of urea and formaldehyde
• (c) cross linked product of phenol and formaldehyde
• (d) linear product of urea and formaldehyde.

Correct Answer: (a)

Explanation: Novolac is a linear condensation polymer of phenol and formaldehyde, which can be further cross-linked to form Bakelite.

22. The correct repeating structural unit of polystyrene is:

• (a) $[ -CH_{2}-CH(C_{6}H_{5}) - ]_{n}$
• (b) $[ -CH_{2}-CH(C_{6}H_{5})-CH(C_{6}H_{5})-CH_{2}- ]_{n}$
• (c) $[ -CH_{2}-CH(C_{6}H_{5})-CH_{2}-CH(C_{6}H_{5})- ]_{n}$
• (d) $[ -CH(C_{6}H_{5})-CH_{2}- ]_{n}$

Correct Answer: (c)

Explanation: Due to the stability of the benzylic radical, phenyl groups appear at alternate carbon atoms along the backbone of the polystyrene chain.

23. Which of the following is not addition copolymer?

• (a) Saran
• (b) Vinyon
• (c) SBR
• (d) PVC

Correct Answer: (d)

Explanation: PVC (Polyvinyl Chloride) is an addition homopolymer made from vinyl chloride. The others are addition copolymers.

24. Soft drinks bottles are generally made up of:

• (a) polyester
• (b) polyurethane
• (c) polystyrene
• (d) polyamide.

Correct Answer: (a)

Explanation: PET (Polyethylene terephthalate), a type of polyester, is the standard material for making beverage bottles.

25. Polymer with highest softening point is:

• (a) LDPE
• (b) HDPE
• (c) teflon
• (d) bakelite.

Correct Answer: (c)

Explanation: Teflon (PTFE) has an exceptionally high softening and melting point due to strong C-F bonds and high crystallinity.

26. The substance used to harden the rubber for tyre manufacture is:

• (a) wax
• (b) 1,3-butadiene
• (c) $CaC_{2}$
• (d) carbon black.

Correct Answer: (d)

Explanation: Carbon black is added to rubber to increase its hardness, tensile strength, and durability for tyre use.

27. Caprolactam can be obtained from:

• (a) benzaldehyde
• (b) cyclohexane
• (c) benzophenone
• (d) adipic acid.

Correct Answer: (b)

Explanation: Industrial production of caprolactam often starts with the oxidation of cyclohexane.

28. Which of the following structures represents neoprene polymer?

• (a) $[ -CH_{2}-C(Cl)=CH-CH_{2}- ]_{n}$
• (b) $[ -CH_{2}-CH(CN)- ]_{n}$
• (c) $[ -CH(C_{6}H_{5})-CH_{2}- ]_{n}$
• (d) $[ -CH_{2}-CH(Cl)- ]_{n}$

Correct Answer: (a)

Explanation: Neoprene is the polymer of chloroprene (2-chloro-1,3-butadiene).

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

• (a) Terylene (Dacron)
• (b) Polyethylene
• (c) Buna-S
• (d) Nylon-6,6

Correct Answer: (a)

Explanation: Terylene is formed by the condensation of ethylene glycol and terephthalic acid.

30. Polystyrene is an example of:

• (a) elastomers
• (b) fibres
• (c) thermoplastic polymers
• (d) thermosetting polymers.

Correct Answer: (c)

Explanation: Polystyrene is a thermoplastic; it is a linear or slightly branched polymer that softens on heating and hardens on cooling.

31. Buna-N is a copolymer of 1,3-butadiene and:

• (a) isoprene
• (b) styrene
• (c) vinyl chloride
• (d) acrylonitrile.

Correct Answer: (d)

Explanation: Copolymerisation of 1,3-butadiene and acrylonitrile in the presence of peroxide gives Buna-N rubber.

32. Elastol is a polymer used to cleanup oil spill. The monomer of elastol is:

• (a) acrylonitrile
• (b) isobutylene
• (c) methyl methacrylate
• (d) styrene.

Correct Answer: (b)

Explanation: Elastol is polyisobutylene, produced from the monomer isobutylene.

33. Find the option showing correctly the name of the polymer and its monomers:

• (a) Kevlar: p-phenylenediamine + terephthaloyl chloride
• (b) Alkyd: Ethylene glycol + phthalic acid
• (c) Dacron: Ethylene glycol + phthaloyl chloride
• (d) Nylon-6,6: Ethylenediamine + adipoyl chloride

Correct Answer: (a)

Explanation: Kevlar is a polyamide produced from p-phenylenediamine and terephthaloyl chloride.

34. Regarding polymerisation reaction find the correct statement:

• (a) R-SH is used as 'chain transfer agent'.
• (b) $BF_{3}$ is an anionic polymerising agent.
• (c) Step growth is alternative for chain-growth.
• (d) AIBN is a free-radical polymerising agent.

Correct Answer: (d)

Explanation: AIBN (Azobisisobutyronitrile) is a well-known initiator for free-radical polymerisation.

35. A biopolymer:

• (a) has a simple structure
• (b) has a linear structure always
• (c) has a polydispersity index = 1
• (d) can never be modified.

Correct Answer: (c)

Explanation: Biopolymers (like proteins) are monodisperse, meaning all molecules have the same mass, so their PDI is 1.

36. Find the incorrect statement:

• (a) Silk is a polyester.
• (b) Cellulose and starch are polysaccharides.
• (c) RNA and DNA are polynucleotides.
• (d) Gutta-Percha is a polymer of isoprene.

Correct Answer: (a)

Explanation: Silk is a natural polypeptide (protein), not a polyester.

37. Find the incorrect match:

• (a) Neoprene : Chloroprene
• (b) Nylon-6: Caprolactam
• (c) Natural rubber: Butadiene
• (d) Perspex: Methyl methacrylate

Correct Answer: (c)

Explanation: Natural rubber is a polymer of isoprene (2-methyl-1,3-butadiene), not simple butadiene.

38. Which one of the following is not an example of chain growth polymer?

• (a) Neoprene
• (b) Buna-S
• (c) PMMA
• (d) Glyptal

Correct Answer: (d)

Explanation: Glyptal is a step-growth polymer formed from ethylene glycol and phthalic acid.

39. High density polythene is manufactured under the conditions:

• (a) 333-343 K temp., 6-7 atm pressure
• (b) 463-483 K temp., 1500 atm pressure
• (c) 150-200 K temp., 1-2 atm pressure
• (d) 763-863 K temp., 1200 atm pressure

Correct Answer: (a)

Explanation: HDPE is produced at low pressures (6-7 atm) and temperatures (333-343 K) using special catalysts.

40. In the preparation of Nylon fibre nitrogen is used:

• (a) to make inert atmosphere
• (b) to increase the rate of reaction
• (c) to decrease the rate of reaction
• (d) none of these.

Correct Answer: (a)

Explanation: Nitrogen provides an inert atmosphere during the polymerization process for Nylon.

41. Which of the following is incorrectly matched?

• (a) Dacron: Ethylene glycol + terephthalic acid
• (b) Nylon 6,6: Hexamethylene diamine + adipic acid
• (c) Bakelite: Phenol + formaldehyde
• (d) Buna-N: 1,3-Butadiene + styrene

Correct Answer: (d)

Explanation: Buna-N is a copolymer of 1,3-butadiene and acrylonitrile. Butadiene and styrene form Buna-S.

42. Which of the following is not a synthetic polymer?

• (a) Polyethylene
• (b) PVC
• (c) Nylon
• (d) Cellulose

Correct Answer: (d)

Explanation: Cellulose is a naturally occurring polysaccharide found in plants.

43. Which of the following acts as a chain transfer agent in vinyl polymerization?

• (a) t-Butyl peroxide
• (b) Carbon tetrachloride
• (c) Diphenylamine
• (d) Phenol

Correct Answer: (b)

Explanation: Carbon tetrachloride ($CCl_{4}$) is used as a chain transfer agent to regulate chain length during vinyl polymerization.

44. Fibre which is resistant to action of chemicals is:

• (a) cotton
• (b) silk
• (c) jute
• (d) terylene.

Correct Answer: (d)

Explanation: Terylene (Dacron) is a synthetic polyester fibre highly resistant to chemicals.

45. Cellulose acetate is a:

• (a) natural rubber
• (b) semi-synthetic polymer
• (c) synthetic polymer
• (d) plasticiser.

Correct Answer: (b)

Explanation: Cellulose acetate is a semi-synthetic polymer produced by the chemical acetylation of natural cellulose.