Q. Nitrobenzene on reaction with conc. $HNO_3/H_2SO_4 $ at $80-100^{\circ} C$ forms which one of the following products ?
Solution:
$NO_2$ group being electron withdrawing reduces electron density at ortho and para-positions. Hence, now the meta-position becomes electron rich on which the electrophile (nitronium ion) attacks during nitration. $HNO_3 + H_2SO_4 \rightarrow \underset{\overset{\downarrow}{H_2O + \downarrow NO_2^+}}{H_2NO_3^+} + HSO_4^- \underset{\text{(nitronium ion)}}{\text{Electrophile}}$
