Which of the following monomeric pair is used to make polymer Nylon 6, 6?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Hexane -1,6-dioic acid and Hexane -1,6-diamine
Nylon 6,6 is a polyamide made by condensation polymerisation of hexamethylenediamine (hexane-1,6-diamine) with adipic acid (hexane-1,6-dioic acid) at high pressure and temperature. The “6,6” shows that each monomer has six carbon atoms. Each –COOH condenses with an –\( \ce{NH2} \) to form an amide link and a molecule of water:
\( \displaystyle n\,\ce{HOOC(CH2)4COOH} + n\,\ce{H2N(CH2)6NH2} \xrightarrow[\text{high pressure}]{553\ \mathrm{K}} \ce{-(NH(CH2)6NHCO(CH2)4CO)_{n}-} + 2n\,\ce{H2O} \)
Why the other options are incorrect
Option (2) Ethane-1, 2-dioic acid and Benzene -1, 4-dicarboxylic Acid — Incorrect. Two acids cannot condense with each other to a polyamide; Dacron (terylene) is made from ethane-1,2-diol and benzene-1,4-dicarboxylic acid.
Option (3) Urea and Methanal — Incorrect. These give urea-formaldehyde resin, used for unbreakable cups.
Option (4) Phenol and Methanol — Incorrect. Bakelite is made from phenol and methanal (formaldehyde), not methanol.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Polyamides – …
