question_answer

Among the following compounds the decreasing order of reactivity towards electrophilic substitution is: [AIPMT 2000]

A)             II > I > III > IV

B) III > I > II > IV

C) IV > I > II > III

D) I > II > III > IV

Correct Answer: A

Solution :

[a] In  and  and  are electron donating group. Hence, they activate the benzene nucleus. In these, order of activation is  while  group deactivates the benzene nucleus. So, it shows lower rate of electrophilic substitution on benzene ring. Thus, order of electrophilic substitution is-