What is the first step in the reaction of an electrophile `(E^(`))` with benzene?

Options

A. Formation of a cyclic onium ion
B. Formation of an aromatic carbocation
C. Formation of a nonaromatic carbocation
D. Formation of nonclassical carbocation

Answer

3

Explanation

The `sigma`- complexed benzenonium ion (sometimes called benzenium ion) is one example of an arenonium or arenium ion, formed by the electrophilic attackon an arene (ArH). It is not aromatic because the cyclic delocalization is interrupted by the `sp^(3)` hybrid C.
In the first step, in the addition to an alkene, a carbocation is formed.
In the second step the arenium ion loses an`H^(+)` regenerating the aromatic `pi` system.It avoids the addition of a nucleophile as a much less stable cyclohexadiene derivative would form. On the other hand, in the case of alkene, the corbocation reacts with a lewis base (nucleophile) to give addition product.