Question

What are \(X\) and \(Y\) respectively in the following reaction? 

• A.
• B.
• C.
• D.

Hint:

Friedel-Crafts alkylation introduces alkyl groups to an aromatic ring, while oxidation with KMnO\(_4\) converts alkyl groups (-CH\(_3\), -CH\(_2\)R) into carboxylic acids (-COOH) when benzylic hydrogen is present.

Answer 1

The Correct Option is C

The reaction involves the following steps:

1. Step 1: Friedel-Crafts Alkylation
- The benzyl halide (CH₃Br) reacts with AlCl₃ to form a benzyl carbocation, which undergoes an electrophilic substitution on the benzene ring.
- This results in the formation of p-chlorotoluene (X) as the major product.

2. Step 2: Oxidation with KMnO₄ in Basic Medium
- The methyl group (-CH₃) in p-chlorotoluene undergoes oxidation by KMnO₄ to form a carboxyl (-COOH) group.
- The final product Y is p-chlorobenzoic acid.

Thus, the correct transformation follows:
X = p-chlorotoluene, Y = p-chlorobenzoic acid
This corresponds to Option (3).