In which electrophilic aromatic substitution reaction an carbocation is formed as an intermediate? A. Nitration B. Alkylation C. Alkanoylation D. Sulfonation E. Halogenation

B. Alkylation

Explanation:

Electrophilic aromatic substitution -

The subsitution reaction, where the hydrogen atom of an aromatic ring is replaced by an external electrophile.

Alkylation reaction -

The subsitution reaction, where the hydrogen atom of an aromatic ring (benzene) is replaced by an alkyl group, is called an alkylation reaction.

The reaction mechanism involves a carbocation intermediate.

Hence, the correct option is B. Alkylation.