Q. Assertion : Replacement of group by in chlorobenzene is easier if nitro group is present in the ring.
Reason: Nitro group leads to strengthening o f the bond in chlorobenzene.

 2072  191 Haloalkanes and Haloarenes Report Error

Solution:

Nitro group is an electron withdrawing group which leads to weakening of bond, hence making it easier to replace the group.