question_answer

The electrophile, E+ attacks the benzene ring to generate the intermediate a-complex. Of the following, which \[P>Q>S>R\]-complex is of lowest energy?

A)                              

B)  

C)                    

D)  

Correct Answer: D

Solution :

                  This structure will be of lowest energy because of resonance stabilisation of positive charge. In all other three structures, the presence of electron-withdrawing \[100mL\] group will destabilise the positive charge and so, they will have greater energy.