Question

Write the chemical reaction when chlorobenzene is heated with conc. HNO₃ in the presence of conc. H₂SO₄.

Answer 1

1. Formation of the Nitronium Ion (Electrophile): The concentrated H₂SO₄ acts as a catalyst to generate the active nitronium ion \[\ce{(NO^+_2)}\] from nitric acid.

\[\ce{HNO3 + 2H2SO4 -> NO^+ + 2H2SO^-_4 + H3O^+}\]

2. Nitration of Chlorobenzene: The chlorobenzene reacts with the nitronium ion to form a mixture of ortho and para-substituted products.

\[\ce{C6H5Cl ->[conc{.} H2SO4][conc{.} HNO3] \underset{o-chloronitrobenzene}{C6H4(Cl)(NO2)} + \underset{p-chloronitrobenzene}{C6H4(Cl)(NO2)} + H2O}\]

Answer 2