Answer the question on the basis of passage given below:
Aldehydes are generally more reactive than ketones in nucleophilic addition reactions due to steric and electronic reasons. Sterically, the presence of two relatively large substituents in ketones hinders the approach of nucleophile to carbonyl carbon more than aldehydes having only one such substituent Electronically aldehydes are more reactive than ketones because two alkyl groups reduce the elctrophilicity of the carbonyl more effectively than in former.

\(A\) will be:

The correct answer is option 3.

The given reactant is propyl benzene. The reaction given is the oxidation of propylbenzene  using potassium permanganate (KMnO_4) in basic conditions \((KOH)\), followed by acidification \((H_3O^+)\).

Oxidation with \( KMnO_4 \) in basic medium:

The alkyl side chain of propylbenzene undergoes complete oxidation, where the entire chain is reduced to a carboxyl group \((-COOH)\). Even though the propyl group  is longer, potassium permanganate oxidizes all carbons attached to the benzene ring down to a single carboxyl group.

Formation of Benzoic Acid:

Once the oxidation is complete, the intermediate potassium carboxylate (benzoate) is formed. Upon acidification with \( H_3O^+ \) (usually in the form of dilute HCl), the carboxylate is protonated, giving benzoic acid \((C_6H_5COOH)\).

Reaction:

No matter the length of the alkyl chain, it will always result in the formation of benzoic acid when using strong oxidizing conditions like those provided by \( KMnO_4 \). The final product of this reaction is benzoic acid (C_6H_5COOH).