Question

Which of the following substrate, on oxidation with alkaline potassium permanganate followed by acid hydrolysis, will NOT give benzoic acid.

• A. n-Butyl benzene
• B. Isopropyl benzene
• C. tert-Butyl benzene
• D. Toluene

Answer 1

The correct option is C tert-Butyl benzene

tert-Butyl benzene, on oxidation with alkaline potassium permanganate followed by acid hydrolysis, will NOT give benzoic acid.
n-Butyl benzene or isopropyl benzene or toluene on oxidation with alkaline potassium permanganate followed by acid hydrolysis, will give benzoic acid.
Only primary and secondary alkyl side chains on the benzene ring (i.e, those containing benzylic hydrogens) are oxidised to carboxylic acids. The tertiary alkyl side chains (which do not contains benzylic hydrogen) are not oxidised.