Question

Chlorobenzene on reaction with acetyl chloride in presence of anhydrous aluminum chloride forms,

• A. 2-Chloroacetophenone
• B. 3-Chloroacetophenone
• C. 4-Chloroacetophenone
• D. 2-Chloroacetophenone and 4-Chloroacetophenone

Hint:

The chlorine atom is an ortho and para director, so both isomers are formed.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
Acetyl chloride with anhydrous \(\text{AlCl}_3\) gives the acylium ion \(\text{CH}_3\text{CO}^+\), so this is a Friedel-Crafts acylation.

Step 2: Directing effect of Cl
In chlorobenzene, Cl withdraws electrons inductively but donates a lone pair by resonance. This raises electron density at the ortho and para positions.

Step 3: Result
The acyl group enters ortho and para to Cl, giving 2-chloroacetophenone and 4-chloroacetophenone. The para product is major because the ortho position is crowded.

Final Answer:
Both 2-chloro and 4-chloroacetophenone are formed, which is option (D). \[ \boxed{\text{(D) }\text{2-Chloroacetophenone and 4-Chloroacetophenone}} \]