• # question_answer 66)   Arrange the following set of compounds in the order of their decreasing relative reactivity with an electrophile. Give reason.

Relative reactivity of the given compounds are : Greater is the $(+R)$ effect of the group, more is the reactivity of the corresponding compound. Or The reactivity of arenes towards electrophiles depends upon their relative electron density in the benzene ring. Higher the electron density (due to strong electron donating groups),more reactive is the arene.