Question

What is Y in the following reaction sequence? 

 

• A.
• B.
• C.
• D.

Hint:

Remember the Friedel-Crafts alkylation reaction and the oxidation of alkylbenzenes with KMnO\(_4\).

Answer 1

The Correct Option is B

1. Reaction of anisole with CH\(_3\)Cl in presence of anhydrous AlCl\(_3\):

This is a Friedel-Crafts alkylation reaction.
The methoxy group (-OCH\(_3\)) is an ortho-para directing group.
The major product (X) will be para-methylanisole (4-methylanisole).

2. Oxidation of 4-methylanisole with KMnO\(_4\)/OH\(^{-}\) followed by H\(_3\)O\(^{+}\):

KMnO\(_4\) in basic medium followed by acidification is a strong oxidizing agent.
It will oxidize the alkyl group attached to the benzene ring to a carboxylic acid group (-COOH).
The methoxy group (-OCH\(_3\)) will remain unaffected.
Y will be 4-methoxybenzoic acid (para-methoxybenzoic acid).

Therefore, Y is 4-methoxybenzoic acid.