How is the electrophile generated in the nitration of benzene?

1 Answer
May 5, 2016

The nitration of benzene involves sulfuric acid and nitric acid, whose pKas are about 3 and 1.3, respectively. Thus, sulfuric acid is the stronger acid and can protonate nitric acid.

The H2O leaving group just dissociates on its own. The full reaction is:

C6H6+H2SO4+HNO3kobs −−C6H5NO2+HSO4+H3O+

Water can form because water has a pKa of about 15.7, and thus its formation in equilibrium is heavily favored in this case.

The electrophile is the bent :..O=(+)N=..O:. Your book may call it the nitronium ion.