\(\mathrm{C}_6 \mathrm{H}_6 \underset{\mathrm{H}_2 \mathrm{SO}_4}{\stackrel{\mathrm{HNO}_3}{\longrightarrow}} X \underset{\mathrm{FeCl}_3}{\stackrel{\mathrm{Cl}_2}{\longrightarrow}} Y\).
In the above sequence \(Y\) can be
3-nitrochlorobenzene
1-nitrochlorobenzene
4-nitrochlorobenzene
none of these.
Solution
$\left(\mathrm{HNO}_3+\mathrm{H}_2 \mathrm{SO}_4\right)$ will generate $\mathrm{NO}_2^{+}$ (nitronium ion) which will give nitrobenzene, as $-\mathrm{NO}_2$ is deactivating and meta directing so, product formed will be 3-nitrochlorobenzene.