Question

What are \(X,\;Y,\;Z\) respectively in the following reaction sequence?

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

An aryl halide containing a \(\mathrm{-NO_2}\) group at the ortho or para position undergoes nucleophilic substitution with aqueous \(\mathrm{NaOH}\) much more readily. \[ \boxed{ p\text{-Nitrochlorobenzene} \xrightarrow[\mathrm{H^+}]{\mathrm{NaOH},\,443\,K} p\text{-Nitrophenol} } \]

Answer 1

The Correct Option is A

Step 1: Nitration of chlorobenzene. Chlorine is an ortho-para directing group. Hence, nitration gives mainly \[ \boxed{p\text{-nitrochlorobenzene}.} \] Thus, \[ \boxed{X=p\text{-nitrochlorobenzene}.} \]

Step 2: Hydrolysis of \(p\)-nitrochlorobenzene. The presence of the strongly electron-withdrawing \[ \mathrm{-NO_2} \] group activates the aryl halide towards nucleophilic substitution. Treatment with \[ \boxed{(i)\ \mathrm{NaOH},\ 443\,K\qquad (ii)\ \mathrm{H^+}} \] replaces chlorine by hydroxyl group. \[ p\text{-Nitrochlorobenzene} \longrightarrow p\text{-Nitrophenol} \] Thus, \[ \boxed{ Y=(i)\ \mathrm{NaOH},\,443\,K,\ (ii)\ \mathrm{H^+} } \] and \[ \boxed{ Z=p\text{-nitrophenol}. } \] Hence, \[ \boxed{(A)} \] is the correct answer.