Question

p-Xylene on reaction with acidified potassium dichromate at high temperature gives ________

(a) benzoic acid

(b) phthalic acid

(c) terephthalic acid

(d) no reaction

The question was asked in class test.

This question is from Methods of Carboxylic Acids Preparation in chapter Aldehydes, Ketones and Carboxylic Acids of Chemistry – Class 12

Answer 1

The correct choice is (c) terephthalic acid

For explanation I would say: p-Xylene is a dimethyl substituted benzene which on vigorous oxidation, gets oxidised to an aromatic dicarboxylic acid, with the two carboxyl groups at para positions with respect to each other. This compound is called terephthalic acid.