Benzene Reactions - Sulfonation, Nitration and Halogenation - Practice Questions & MCQ

Benzene undergoes chlorination when it is treated with chlroine in presence of Lewis catalyst such as AlCl₃ or Fe or FeCl₃ and in absence of light.

For example:

Mechanism
The mechanism of this reaction follows two step:

NOTE: The hydrogen is removed by the AlCl⁻₄ ion which was formed in the first stage. The aluminum chloride catalyst is re-generated in this second stage.

Nitration
Benzene undergoes nitration when treated with concentrated nitric acid in the presence of concentrated sulphuric acid, i.e, nitrobenzene is formed. The reaction is carried out at 313-323 K when one of the H atom from the benzene ring is replaced by the nitro group.

For example:

Sulphonation
Benzene forms benzene sulphonic acid with hot concentrated sulphuric acid or with fuming sulphuric acid (oleum). The attacking electrophile in the reaction is Sulphur trioxide 

For example: