Question

p-Chloronitrobenzene undergoes nucleophile substitution faster than chlorobenzene. Explain.

Answer 1

Hint: In this question remember that p-chloronitrobenzene consists of a nitro group which is an electron withdrawing group whereas chlorobenzene doesn’t consist of a nitro group in it, use this information to approach the answer.

Complete answer:
p-chloronitrobenzene undergoes nucleophilic substitution faster than chlorobenzene because p-chloronitrobenzene have nitro group which is electron withdrawing group and chlorine itself is a electronegative group by which chlorine generate electron on its surface and attract as well as it also generate partial positive charge therefore now it become an electrophile and it require electron for that positive charge then the nitro group withdraw its electron and increase the partial positive charge over carbon and chloro group and weaken their bond therefore it goes easily on nucleophilic substitution reaction than chlorobenzene.

Note:
In the above solution we came across the term “nucleophilic substitution” which can be explained as the organic reactions where compound which is rich in electron (nucleophilic) replaces leaving group so the compound which have the more electron withdrawing group the faster the nucleophilic substitution occurs.