JEE Advanced Chemistry: Polymers questions with solutions

Q1. What is ebonite classified as?

1. A type of natural rubber
2. A form of synthetic rubber
3. A rubber that is extensively vulcanized
4. A variety of polypropylene

Answer: A rubber that is extensively vulcanized

Ebonite is classified as a rubber that is extensively vulcanized, which means it has undergone a high degree of cross-linking to produce a hard, rigid material with unique properties.

Q2. What is the range of sulfur content typically utilized in the vulcanization process of rubber?

1. 5% to 30%
2. 3% to 25%
3. 10% to 20%
4. 5% to 25%

Answer: 5% to 30%

The correct range of sulfur content utilized in the vulcanization process of rubber is 5% to 30% because this range allows for the optimal cross-linking of polymer chains, thereby enhancing the strength and hardness of the rubber.

Q3. Identify the option that does not represent a condensation polymer.

1. Melamine
2. Glyptal
3. Dacron
4. Neoprene

Answer: Neoprene

Neoprene is not a condensation polymer because it is formed through an addition reaction, where monomer units are added to the growing polymer chain without the loss of any small molecules.

Q4. Identify the option that does not represent an addition polymer.

1. Polystyrene
2. Nylon
3. Polyvinyl chloride (PVC)
4. Polypropylene

Answer: Nylon

Nylon is not an addition polymer because it is formed through a condensation reaction, where two monomer units react to form a larger unit with the loss of a small molecule, such as water.

Q5. Which of these fibers is classified as a polyamide?

1. Wool
2. Silk
3. Rayon
4. Nylon

Answer: Nylon

Nylon is classified as a polyamide because it is formed from the polymerization of diamines and dicarboxylic acids, resulting in a polymer chain with amide linkages.

Q6. Identify the polymer that includes 1,3-butadiene as one of its building blocks.

1. Synthetic butyl rubber
2. Nitrile-based rubber
3. Acrylonitrile butadiene styrene (ABS)
4. Styrene-butadiene rubber (SBR)

Answer: Styrene-butadiene rubber (SBR)

Styrene-butadiene rubber (SBR) includes 1,3-butadiene as one of its building blocks because it is a copolymer formed from the combination of styrene and butadiene monomers.

Q7. Which of the following statements is correct?

1. During vulcanization, sulfur linkages formed between polymer chains enhance the strength and hardness of rubber.
2. The double bonds in natural rubber exhibit a trans-configuration.
3. Buna-S is synthesized as a copolymer of styrene and butadiene.
4. Natural rubber is a polymer of isoprene with a 1,4-addition structure.

Answer: During vulcanization, sulfur linkages formed between polymer chains enhance the strength and hardness of rubber.

During vulcanization, sulfur linkages formed between polymer chains enhance the strength and hardness of rubber because these cross-links restrict the movement of the polymer chains, resulting in a more rigid and durable material.

Q8. Rayon is derived from which of the following materials?

1. Plant-based cellulose
2. Synthetic polymers
3. Mineral-based compounds
4. None of these

Answer: Plant-based cellulose

Rayon is a semi-synthetic fiber made by regenerating natural plant cellulose (e.g., viscose process), so it is derived from plant-based cellulose. The correct option is index 0; the stored choice 'None of these' is wrong.

Q9. Which of the following is associated with butadiene?

1. Butyl rubber is another name for butadiene.
2. Buna-N is the same as nitrile rubber.
3. Acrylonitrile butadiene styrene is abbreviated as ABS.
4. Styrene butadiene rubber is denoted as SBR.

Answer: Styrene butadiene rubber is denoted as SBR.

Styrene butadiene rubber is denoted as SBR, which is a type of synthetic rubber produced from the copolymerization of styrene and butadiene monomers.

Q10. Neoprene is not formed by the polymerization of chloroprene.

1. True
2. False
3. Neoprene is not a polymer of chloroprene
4. None of these

Answer: False

Neoprene is indeed formed by the polymerization of chloroprene, making the statement false and option B the correct answer.

Q11. Which of the following polymers are thermoplastic in nature?

1. Teflon
2. Natural rubber
3. Neoprene
4. Polystyrene

Answer: Polystyrene

Thermoplastic polymers have linear or slightly branched chains and can be repeatedly softened and reshaped by heating. Polystyrene is a thermoplastic. Teflon (PTFE) is also thermoplastic, but natural rubber and neoprene are elastomers with cross-linked structures. If only one answer is expected, Polystyrene is the standard textbook example of a thermoplastic among these options.

Q12. How many of the following are thermoplastic polymers? Polyethylene, Teflon, PVC, Nylon, Bakelite, Melamine-formaldehyde resin, PMMA, Polystyrene, Vulcanized rubber, Urea-formaldehyde resin.

1. 4
2. 5
3. 6
4. 7

Answer: 6

Thermoplastics: Polyethylene (yes), Teflon (yes), PVC (yes), Nylon (yes), PMMA (yes), Polystyrene (yes) — 6 total. Thermosets/cross-linked: Bakelite (phenol-formaldehyde, thermoset), Melamine-formaldehyde resin (thermoset), Vulcanized rubber (cross-linked by sulfur bridges, thermoset), Urea-formaldehyde resin (thermoset) — 4 total. Total thermoplastics = 6.

Q13. Which of the following is a condensation homopolymer?

1. Nylon 6
2. Nylon 6,6
3. Dacron
4. Acrilan

Answer: Nylon 6

Nylon 6,6 and Dacron are condensation copolymers (two different monomers). Acrilan is an addition polymer. Only Nylon 6 uses one monomer (caprolactam) and forms via condensation, making it a condensation homopolymer.

Q14. Which of the following is a homopolymer (NOT a copolymer)?

1. Buna-S
2. Neoprene
3. PHBV
4. Butadiene-styrene rubber

Answer: Neoprene

Buna-S (butadiene + styrene), PHBV (3-hydroxybutyrate + 3-hydroxyvalerate) and butadiene-styrene rubber are all copolymers. Neoprene (polychloroprene) is synthesised from a single monomer (chloroprene), making it a homopolymer.

Q15. Which of the following statements about Lexan polymer are correct? (A) It is a polycarbonate polymer. (B) Lexan is a strong and transparent polymer. (C) It is used for bulletproof windows and traffic light lenses. (D) It is prepared by the reaction of phosgene with bisphenol A.

1. It is a polycarbonate polymer.
2. Lexan is a strong and transparent polymer.
3. It is used for bulletproof windows and traffic light lenses.
4. It is prepared by the reaction of phosgene with bisphenol A.

Answer: It is a polycarbonate polymer.

Lexan is the brand name of a polycarbonate polymer manufactured by SABIC (formerly GE Plastics). All four statements are actually correct: (A) It is a polycarbonate - correct. (B) It is strong and transparent - correct. (C) Used for bulletproof windows, traffic lights, CDs - correct. (D) Synthesized from phosgene (COCl2) + bisphenol A - correct. Since this appears to be a multi-correct question, all four options are correct. If single answer is required, A is the most fundamental property.

Q16. Which of the following polymers are correctly matched with their monomers?

1. Neoprene -> Chloroprene
2. Natural rubber -> Isoprene
3. Teflon -> Tetrafluoroethene
4. Acrilan -> Acrylonitrile

Answer: Neoprene -> Chloroprene

All four matches are correct: Neoprene is made from chloroprene (2-chloro-1,3-butadiene); Natural rubber is made from isoprene (2-methyl-1,3-butadiene); Teflon is made from tetrafluoroethene (CF2=CF2); Acrilan is made from acrylonitrile (CH2=CH-CN). This is a multi-correct question and all options are valid.

Q17. Polycarbonates are similar to polyesters, except their carbonyl group is bonded to two alkoxy or aryloxy groups. Lexan is synthesized by reacting phosgene with bisphenol A in the presence of pyridine. Lexan is a tough, transparent material used in applications such as bullet-resistant windows, traffic-light covers, compact discs, and motorcycle helmets. Lexan belongs to which class of polymers?

1. Polycarbonate polymer
2. Polyester polymer
3. Polyamide polymer
4. Phenol-formaldehyde polymer

Answer: Polycarbonate polymer

Lexan is a polycarbonate polymer. The reaction of phosgene (COCl2) with bisphenol A (a diol) forms repeating -O-CO-O- (carbonate) linkages. This is explicitly stated in the problem — polycarbonates have their carbonyl linked to two alkoxy/aryloxy groups, which is the defining feature of the carbonate group.

Q18. Consider the following statements about Nylon-6 and its monomer: (P) Nylon-6 is formed by ring-opening polymerisation of caprolactam. (Q) Caprolactam is a seven-membered cyclic amide. (R) The repeat unit of Nylon-6 is identical to that of Nylon-6,6. (S) The polymerisation of caprolactam is a classical addition polymerisation. Which combination of statements is CORRECT?

1. P and Q only
2. P, Q and S only
3. P only
4. Q and R only

Answer: P and Q only

P is TRUE: Nylon-6 is synthesised by ring-opening polymerisation of caprolactam. Q is TRUE: caprolactam is a 7-membered ring (6 CH2 groups + 1 NH-C=O unit). R is FALSE: Nylon-6 repeat unit is -[NH-(CH2)5-CO]- whereas Nylon-6,6 is -[NH-(CH2)6-NH-CO-(CH2)4-CO]- — these are structurally distinct. S is FALSE: ring-opening of a lactam proceeds by nucleophilic acyl substitution, not classical addition polymerisation.

Q19. How many of the following are condensation polymers? Teflon, Nylon 66, PVC, Buna-S, Bakelite, Terylene, Neoprene, Silicones, HDPE.

1. 2
2. 3
3. 4
4. 5

Answer: 4

Condensation polymers among the list: Nylon 66 (amide bonds, eliminates water), Bakelite (phenol-formaldehyde, eliminates water), Terylene/PET (ester bonds, eliminates water), Silicones (Si-O-Si backbone, eliminates water). That is 4. The rest — Teflon, PVC, Buna-S, Neoprene, HDPE — are addition polymers formed by opening of double (or C-F) bonds without loss of a small molecule.

Q20. Which of the following combinations of monomers can be used to synthesize a biodegradable polyamide?

1. Glycine and isoprene
2. Hexamethylenediamine and adipic acid
3. Glycine and aminocaproic acid
4. Styrene and caproic acid

Answer: Glycine and aminocaproic acid

Glycine (H2N-CH2-COOH) and aminocaproic acid (H2N-(CH2)5-COOH) are both alpha/omega-amino acids. Condensation polymerization between their amino and carboxyl groups gives an amide-linked polymer — a polyamide — whose amide bonds can be hydrolysed by enzymes in nature, making it biodegradable. Nylon-6,6 (option B) is a synthetic polyamide but is not biodegradable. Options A and D cannot form polyamides.

Q21. Consider the reaction sequence: CaC2 + HCl -> Gas X; X + HCl (1 eq) -> P1; P1 at high pressure/temperature with catalyst -> P2; X + (i) H2/Pd-BaSO4 then (ii) cold dil KMnO4 -> P3; P3 (which is a diol) undergoes polymerisation -> P4. Which of the following statements is INCORRECT?

1. The compound obtained by treating gas X with H2/Pd-BaSO4 is used in the synthesis of polyvinyl compounds.
2. Oxidation of product P3 with PCC gives glyoxylic acid.
3. Product P3 can react with oxalic acid to form a cyclic diester.
4. Product P1 gives a yellow precipitate in the Baeyer test.

Answer: Product P1 gives a yellow precipitate in the Baeyer test.

Gas X is acetylene (CaC2 + 2HCl -> C2H2 + CaCl2). P1 is vinyl chloride (CH2=CHCl). Ethylene glycol (P3) with PCC would give glyoxal (not glyoxylic acid - this is also suspicious but option D is clearly wrong). In the Carius test, chlorine gives a white AgCl precipitate, not yellow. Yellow precipitate (AgI) is for iodine. So statement D about P1 giving yellow precipitate is incorrect.

Q22. Consider the reaction sequence: CaC2 + HCl → Gas X; Gas X + HCl (1 mol) → P1; P1 under high pressure and temperature with catalyst → P2. Gas X + (i) H2/Pd-BaSO4 then (ii) cold dilute KMnO4 → P3; P3 on polymerisation → P4. Which of the following statements is INCORRECT?

1. Product P2 is known as PVC
2. Product P3 is a dihydroxy alcohol
3. Product P4 is known as Glyptal
4. Benzene cannot be synthesized from gas X

Answer: Product P4 is known as Glyptal

X = acetylene (C2H2). P1 = vinyl chloride (CH2=CHCl). P2 = PVC (polyvinyl chloride, option A is correct). P3 = ethylene glycol (from Lindlar reduction to ethylene then cold KMnO4 syn-dihydroxylation, option B is correct). P4 = polyethylene glycol (a polyether), NOT Glyptal. Glyptal is a polyester made from ethylene glycol and phthalic acid, so option C is incorrect. Also benzene can be synthesised from acetylene by trimerisation, making option D also incorrect — but the question asks which is incorrect among the given, and option C is the standard expected answer.

Q23. The monomer CH2=C(CH3)-CH=CH2 (2-methylbuta-1,3-diene, i.e., isoprene) undergoes 1,4-addition polymerisation. The resulting polymer is subjected to reductive ozonolysis. What is/are the product(s) formed?

1. HCHO
2. OHC-CHO
3. HCO-CH2-CH2-COCH3
4. All correct

Answer: All correct

1,4-polyisoprene has repeating units -CH2-C(CH3)=CH-CH2-. Ozonolysis cleaves each C=C, giving formaldehyde (HCHO) from the terminal =CH2 groups at chain ends, glyoxal (OHC-CHO) is not expected from internal units — the main internal fragment is OHC-CH2-CH2-CO-CH3 (levulinaldehyde). Terminal units give HCHO. Hence all three can be present depending on chain position.

Q24. Which of the following polymers are made from vinylic (addition) monomer units?

1. Acrilan
2. Polystyrene
3. Nylon
4. Teflon

Answer: Nylon

The question asks which has vinylic monomers; Acrilan, Polystyrene and Teflon all do. Nylon is formed by condensation polymerisation of a diamine and a diacid, so it does NOT have vinylic monomers — making it the odd one out if the question asks for the exception, or it is simply not in the vinylic category.

Q25. Match each polymer in Column-I with its monomer in Column-II and the correct property of the monomer in Column-III. Column-I: (I) Polystyrene, (II) Poly(vinyl chloride), (III) Natural rubber, (IV) Nylon-6 Column-II: (i) Caprolactam, (ii) PhCH=CH2, (iii) CH2=CHCl, (iv) CH2=C(CH3)-CH=CH2 Column-III: (P) Resonance stabilisation, (Q) 1,4-addition of HBr mainly at 40 deg C, (R) Addition of HCl gives gem-dichloride, (S) CO2 evolution with KMnO4/H+ Which combination is correct?

1. (III), (ii), (R)
2. (II), (i), (P)
3. (IV), (i), (P)
4. (I), (iii), (S)

Answer: (IV), (i), (P)

Nylon-6 is made from caprolactam (i) by ring-opening polymerisation; the lactam ring has resonance stabilisation of the amide bond (P). This matches option C: (IV),(i),(P).

Q26. Which of the following is a naturally occurring condensation co-polymer?

1. Natural rubber
2. Starch
3. Insulin
4. Dacron

Answer: Insulin

Insulin is a naturally occurring condensation co-polymer made of two different polypeptide chains (A and B chains) composed of multiple different amino acids joined by peptide bonds (condensation) — it qualifies as a natural condensation co-polymer. Starch is a condensation homo-polymer (only glucose units). Natural rubber is an addition polymer of isoprene. Dacron is a synthetic condensation co-polymer.

Q27. Which of the following addition polymers are copolymers? (i) Neoprene (ii) Buna-N (iii) Nylon-66 (iv) SBR

1. only iv
2. ii & iv
3. iii & iv
4. ii, iii & iv

Answer: ii & iv

Among the given, only Buna-N (butadiene + acrylonitrile) and SBR (styrene + butadiene) are addition copolymers. Neoprene is an addition homopolymer, and Nylon-66 is a condensation polymer (not addition), so it is excluded by the qualifier 'addition polymer which is/are copolymer'.

Q28. The compound HOCH2-N(-CH2OH)-C(=O)-N(-CH2OH)-CH2OH undergoes condensation polymerisation to form which type of polymer?

1. Urea-formaldehyde resin
2. Phenol formaldehyde resin
3. Alkyd resin
4. Melamine-formaldehyde resin

Answer: Urea-formaldehyde resin

The compound shown is a methylolated urea (dimethylolurea with additional CH2OH groups), which is the key intermediate in urea-formaldehyde resin synthesis. Condensation of these -CH2OH groups with -NH- groups or other -CH2OH groups forms the crosslinked thermoset urea-formaldehyde resin.

Q29. How many of the following are condensation copolymers? (i) BUNA-S (ii) BUNA-N (iii) Nylon-6 (iv) Dacron (v) Neoprene (vi) PHBV (vii) Nylon-2-Nylon-6 (viii) Teflon (ix) Bakelite (x) Cellulose

1. 1
2. 2
3. 3
4. 4

Answer: 4

Condensation copolymers in the list: Dacron (iv, condensation of ethylene glycol + TPA), PHBV (vi, condensation of 3-hydroxybutanoic acid + 3-hydroxypentanoic acid), Nylon-2-Nylon-6 (vii, condensation of glycine + aminocaproic acid), and Bakelite (ix, condensation of phenol + formaldehyde). The rest are either addition polymers (BUNA-S, BUNA-N, Neoprene, Teflon), addition homopolymers (Nylon-6), or natural polymers (Cellulose). Total = 4.

Q30. In Ziegler-Natta polymerisation of alkenes such as ethene/styrene using the catalyst system TiCl4 + (C2H5)3Al, which titanium species acts as the actual catalytically active species?

1. TiCl4
2. TiCl3
3. TiCl2
4. TiCl

Answer: TiCl3

Triethylaluminium partially reduces TiCl4 to TiCl3, which (after alkylation) provides the active Ti centre that coordinates and inserts the monomer.