On treatment of chlorobenzene with chloromethane in the presence of Na/dry ether, the major product obtained is:
Toluene
— This reaction is an example of the Wurtz-Fittig reaction.This reaction is an example of the Wurtz-Fittig reaction.
Concept: The Wurtz-Fittig reaction is a modification of the Wurtz reaction. It is used to synthesize alkylarenes by reacting an aryl halide with an alkyl halide in the presence of sodium metal and dry ether. The sodium metal removes the halogen atoms from both the aryl and alkyl halides, forming a new carbon-carbon bond between the aryl and alkyl groups.
Why (D) is correct:
In this reaction, chlorobenzene (aryl halide) reacts with chloromethane (alkyl halide) in the presence of sodium (Na) and dry ether. The aryl group from chlorobenzene combines with the methyl group from chloromethane to form toluene.
The balanced chemical equation is:
The major product obtained is toluene.
Option Analysis:
- A) Diphenyl: Diphenyl would be formed if two molecules of chlorobenzene reacted with sodium (Fittig reaction), not with chloromethane.
- B) Ethane: Ethane would be formed if two molecules of chloromethane reacted with sodium (Wurtz reaction), not with chlorobenzene.
- C) o-Chlorotoluene: o-Chlorotoluene is not the product of this reaction. This would imply substitution on the benzene ring, which is not the mechanism of the Wurtz-Fittig reaction.
- D) Toluene: This is the correct product as explained above.
Correct Answer: (D)
Toluene