Question

Halogen is ring activator or deactivator? Explain.

Answer 1

Dear student ,
In real manner Halogens are ring deactivator although they are ortho / para directing groups
Reason : Since we know that halogen contains l.p. which is the necessary condition of +M effect but halogens do not show + M effect strongly this is due to the fact that the l.p. electrons and the pie electrons of the Carbon of the ring are not co-planer so , in all aryl halides - I is dominant over + M effect , that is why they are deactivating groups .
Regards