Nitrobenzene can be prepared from benzene by using a mixutre of conc $\mathrm{HNO}_3$ and conc.…
Nitrobenzene can be prepared from benzene by using a mixutre of conc $\mathrm{HNO}_3$ and conc. $\mathrm{H}_2 \mathrm{SO}_4$. In the mixture, nitric acid acts as a/an :
reducing agent
acid
base
catalyst
Solution
Key Idea Proton donor are acids and proton acceptor are bases.
Conc. $\mathrm{H}_2 \mathrm{SO}_4$ and conc. $\mathrm{HNO}_3$ react in the following manner :
$\begin{aligned}
& \underset{\text { base }}{\mathrm{HNO}_3}+\underset{\text { acid }}{\mathrm{H}_2 \mathrm{SO}_4} \longrightarrow \mathrm{H}_2 \mathrm{NO}_3^{+}+\mathrm{HSO}_4^{-} \\
& \mathrm{H}_2 \mathrm{NO}_3^{+} \longrightarrow \underset{\substack{\text { nitronium } \\
\text { ion }}}{\mathrm{NO}_2^{+}}+\mathrm{H}_2 \mathrm{O} \\
&
\end{aligned}$
Hence, in this reaction $\mathrm{HNO}_3$ acts as a base and $\mathrm{H}_2 \mathrm{SO}_4$ as an acid.