CD 12.4 Reactions of Arenes: Nitration of Benzene

The nitration of benzene requires a nitrating mixture composed of concentration sulfuric acid and concentrated nitric acid.
The overall equation for the reaction is:

This nitrating mixture provides the electrophile for the electrophilic substitution reaction:

The electrophile is NO₂⁺, as a positively charged molecule it is attracted towards the negative charge of the electrons. 

Therefore the  NO₂⁺ attacks the benzene and binds to a carbon atom in the ring. A carbocation is formed (a positive carbon atom) and the delocalised system of electrons is momentarily disrupted. To fix this, the carbon pinches the electrons from the bond with hydrogen, and a hydrogen ion is released. 

If the temperature is over 55 degrees, further substitution will occur to produce compounds like the ones below.

The video above goes through the whole process in more detail, but its just like the other reactions in terms of it's mechanism.

It has appeared a couple of times in past papers, and they like talk about the nitrating mixture (ie. which acid acts as a base, which acid is stronger etc.)

Answers for the question below can be found here.