JEE Main 2021 · 25 July · evening · Single correct · +4 / −1
A biodegradable polyamide can be made from :
- (a) Glycine and isoprene
- (b) Hexamethylene diamine and adipic acid
- (c) Glycine and aminocaproic acid
- (d) Styrene and caproic acid
Answer and solution
Answer (c) Glycine and aminocaproic acid
Solution
Chemistry ma’am · 3 steps
You need amide links, and you need them from amino acids. That points straight to nylon-2-nylon-6.
- Polyamide first. A polyamide needs -CO-NH⁻ links, so the monomers must carry -NH₂ and -COOH groups. Monomers that only have C=C bonds give addition polymers, not amides.
- Then biodegradable. Microbes break down a polymer easily when its pieces resemble natural ones. Amino acid units such as glycine are exactly that kind of piece.
Monomers Amide links possible? Biodegradable? Glycine + isoprene No, isoprene is a diene with no -NH₂ or -COOH Not a polyamide Hexamethylene diamine + adipic acid Yes, gives nylon-6,6 No Glycine + aminocaproic acid Yes, both are amino acids Yes, nylon-2-nylon-6 Styrene + caproic acid No, there is no amine group anywhere Not a polyamide - So. Glycine (H₂N-CH₂-COOH) and aminocaproic acid (H₂N-(CH₂)₅-COOH) condense into the biodegradable copolymer nylon-2-nylon-6. The answer is (c).
The idea to keep. For biodegradable polymers, remember the two standard ones: PHBV (from hydroxy acids) and nylon-2-nylon-6 (from glycine and aminocaproic acid). Both are built from units that nature can digest.
Answer from the NTA final answer key. Solution by PrepWiser.