JEE Main 2022 · 26 June · morning · Single correct · +4 / −1
Which of the following sets are correct regarding polymer?
(A) Copolymer : Buna-S
(B) Condensation polymer : Nylon-6,6
(C) Fibres : Nylon-6,6
(D) Thermosetting polymer : Terylene
(E) Homopolymer : Buna-N
Choose the correct answer from given options below :
- (a) (A), (B) and (C) are correct
- (b) (B), (C) and (D) are correct
- (c) (A), (C) and (E) are correct
- (d) (A), (B) and (D) are correct
Answer and solution
Answer (a) (A), (B) and (C) are correct
Solution
Chemistry ma’am · 3 steps
Ask two things of each polymer: how many monomers made it, and does it soften when heated?
- Know the monomers. A homopolymer is built from one kind of monomer and a copolymer from two or more. A condensation polymer forms when two monomers join and lose a small molecule such as H₂O at each link.
- Know the heat behaviour. Fibres are long chains with strong intermolecular forces, such as hydrogen bonds. They soften on heating, so they are thermoplastic. Thermosetting polymers like Bakelite form a rigid cross-linked network that does not soften again.
Statement What the polymer actually is Verdict (A) Copolymer : Buna-S 1,3-butadiene + styrene, two monomers Correct (B) Condensation polymer : Nylon-6,6 hexamethylenediamine + adipic acid, losing H₂O Correct (C) Fibres : Nylon-6,6 polyamide chains held by hydrogen bonds, drawn into threads Correct (D) Thermosetting polymer : Terylene polyester fibre from ethylene glycol + terephthalic acid, softens on heating Wrong (E) Homopolymer : Buna-N 1,3-butadiene + acrylonitrile, two monomers, so a copolymer Wrong - So. Only (A), (B) and (C) are correct. Any option that includes (D) or (E) is out, which leaves (a).
The idea to keep. Every Buna rubber is a copolymer: butadiene with styrene (S) or with acrylonitrile (N). Terylene and nylon-6,6 are condensation fibres that soften on heating, so neither is thermosetting.
Answer from the NTA final answer key. Solution by PrepWiser.