Question

Describe method of nitration of benzene.

Answer 1

Nitration happens when one (or more) of the hydrogen atoms on the benzene ring is replaced by a nitro group, NO2. Benzene is treated with a mixture of concentrated nitric acid and concentrated sulphuric acid at a temperature not exceeding 50°C. The mixture is held at this temperature for about half an hour.

Answer 2

Nitration of Benzene: Benzene reacts with concentrated nitric acid at 323-333k in the presence of concentrated Sulphuric acid to form nitrobenzene. This reaction is known as nitration of benzene.

Mechanism for nitration of benzene:

Step 1: Nitric acid accepts a proton from sulphuric acid and then dissociates to form nitronium ion.



Step 2: The nitronium ion acts as an electrophile in the process which further reacts with benzene to form arenium ion.

Step 3: The arenium ion then loses its proton to Lewis base forming nitrobenzene.