Answer:
Option A
Explanation:
An electron releasing group stabilises the carbocation by dispersing its positive charge and thus activates the ring while an electron-withdrawing group destabilises the carbocation by intensifying its positive charge and thus deactivates the ring.
-NH2 being electron releasing group releases electron and thus tend to neutralise the positive charge of the ring and itself becomes somewhat positive. The dispersal of the positive charge of the ring stabilises carbocation and hence facilitates its formation which ultimately results in an increased rate of reaction. Now since such factor is not present in benzene, its carbocation is less stable than (A). hence aniline undergoes electrophilic substitution at a faster rate than benzene.
On the other hand in (C) the -NO2 group (an electron-withdrawing group) intensifies positive charge on the ring and thus destabilises the carbocation and hence its formation becomes difficult which ultimately results in a slower reaction. Now since substituent is not present in benzene, its carbocation (B) is relatively more stable than (C). Hence nitrobenzene undergoes electrophilic substitution at a slower rate than benzene
