JEE Main levelSingle correct optionDifficulty 2 of 3pl063
The repeat unit of nylon 6 is −[NH−(CHX2)Xx−CO]X−. The value of x is
A4
B6
C3
D5
Answer: D
Nylon 6 comes from caprolactam, a six-carbon cyclic amide. Six carbons in the repeat unit include the carbonyl carbon, leaving five CHX2 groups, so x=5.