Question

Identify 'A' in the following reaction.
A + Acetyl chloride $\xrightarrow[AlCl_3]{anhydrous}$ 2-Chloroacetophenone + 4-Chloroacetophenone}

• A. Benzene
• B. Chlorobenzene
• C. Toluene
• D. Phenol

Hint:

Halogens are ortho-para directing but deactivating in electrophilic aromatic substitution.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The reaction is a Friedel-Crafts acylation. We need to find the starting aromatic compound 'A' that yields chloro-substituted acetophenones.
Step 2: Detailed Explanation:
1. The products are 2-chloroacetophenone (ortho) and 4-chloroacetophenone (para).
2. The "acetophenone" part comes from the acetyl chloride ($CH_3COCl$) in the presence of $AlCl_3$.
3. The presence of a chlorine atom on the benzene ring in the products implies that the reactant 'A' must already have a chlorine atom attached.
4. Chlorobenzene undergoes electrophilic substitution. The chlorine atom is ortho/para directing due to its $+M$ effect.
5. Thus, Chlorobenzene reacting with acetyl chloride gives ortho and para chloroacetophenones.
Step 4: Final Answer:
Reactant 'A' is Chlorobenzene.