Question

Among the following compounds the decreasing order of reactivity towards electrophilic substitution is

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

Answer 1

The correct option is B

III > I > II > IV

In $-C{H}_3,-OC{H}_3$ and $C{F}_3,C{H}_3$ and $-OC{H}_3$ are electron donating group. Hence, they activate the benzene nucleus. In these, order of activation is $-OC{H}_3>-C{H}_3$ while $-C{F}_3$ group deactivates the benzene nucleus. So, it shows lower rate of electrophilic substiution on benzene ring. Thus, order of electrophilic substitution is