Question

The correct order of reactivity towards the electrophilic substitution of the compounds aniline (I), benzene (II) and nitrobenzene (III) is

• A. II < III > I
• B. I > II > III
• C. III > II > I
• D. II > III > I

Answer 1

Answer: (B)

In aniline -$N{H}_2$ group is attached with benzene ring. - $N{H}_2$ group shows $+M$-effect. So, it activates the benzene ring. Hence, rate of electrophilic substitution is increased due to increase in the electron density at o/p-position. In case of nitrobenzene, ($-N{O}_2$) -M-effect group deactivates the benzene ring, so in nitrobenzene rate of electrophilic substitution is lower than benzene. Hence, order of $SE$ reaction is