Given In the above compounds correct order of reactivity in electrophilic substitution reactions will be:

Step-by-step solution

- Cl and - CH ₃ groups are o and p directing. They are electron releasing due to + E and +M effects. Further since such groups increase electron density in the nucleus, they facilitate further electrophilic substitution and hence known as activating group. The activating effect of these groups is in order of - CH ₃>- X but chlorine exceptionally deactive the ring due to strong - I effect. Hence, it is difficult to carry out substitution in chlorobenzene than in benzene. Further - NO ₂ is a deactivating group hence