Question

Identify the product of the reaction:

• A. 1-chloro-2-methylbenzene
• B. 1-chloro-3-methylbenzene
• C. 1-chloro-4-methylbenzene
• D. 2-chloro-1,4-dimethylbenzene

Hint:

When performing electrophilic aromatic substitution, electron-donating groups like -CH\(_3\) direct the incoming electrophile to the ortho and para positions. The para position is usually the favored position.

Answer 1

The Correct Option is B

This reaction involves chlorination of toluene CH\(_3\)C\(_6\)H\(_5\)using chlorine Cl\(_2\) in the presence of iron(III) bromide (FeBr\(_3\)) as a catalyst. This is an example of electrophilic aromatic substitution, where the chlorine atom will substitute a hydrogen atom on the benzene ring. In the case of toluene (methylbenzene), the methyl group (-CH\(_3\)) is an electron-donating group and directs the incoming electrophile (chlorine) to the ortho and para positions relative to itself. However, since para substitution is more favored due to steric reasons, the chlorination will predominantly occur at the para position to the methyl group. Thus, the major product is 1-chloro-3-methylbenzene (since 1-chloro-3-methylbenzene is the para position for the methyl group).