Question

The major product obtained in the following reaction is Chlorobenzene + chlorine $\xrightarrow{\text{Anhydrous }\text{FeCl}_3}$ product (Major)

• A. 1, 3, 5-trichlorobenzene
• B. 1, 4-dichlorobenzene
• C. 1, 2-dichlorobenzene
• D. 1, 3-dichlorobenzene

Hint:

For almost all ortho/para-directing substitutions on monosubstituted benzene rings, the para-product is structurally favored as the major product due to minimized steric clash.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The query asks for the principal product of chlorobenzene's reaction with Cl₂ gas in the presence of an FeCl₃ catalyst.

Step 2: Key Formula or Approach:
The chlorine substituent on the ring acts as an ortho/para-director because of its +R (resonance) effect from lone pair donation.

Step 3: Detailed Explanation:
The resonance effect enriches the ortho and para positions with electron density, making them the sites for electrophilic attack by Cl⁺. The para product (1,4-dichlorobenzene) is favored as the major isomer due to reduced steric hindrance compared to the ortho product.

Step 4: Final Answer:
The major product formed is 1,4-dichlorobenzene, which matches option (B).