Question

What is the correct IUPAC name of the shown compound?

(a) 2-Carboxylmethylcyclopentane

(b) 2-Methylcyclopentanecarboxylic acid

(c) 2-Methylcyclopentanoic acid

(d) (2-Methylcyclopentyl)carboxylic acid

I had been asked this question during an interview.

Question is taken from Nomenclature and Structure of Carboxyl Groups topic in portion Aldehydes, Ketones and Carboxylic Acids of Chemistry – Class 12

Answer 1

Correct option is (b) 2-Methylcyclopentanecarboxylic acid

Easiest explanation: The compound is a cyclic carboxylic acid with five carbon atoms in the cyclic ring and one carboxyl group. The methyl group is present as a substituent at the adjacent position on the ring. Hence, it is named as a derivative of cyclopentanecarboxylic acid.