Rate of the reaction is fastest when Z is (a) Cl.

Question

Rate of the reaction

Answer 1

Reactivity of the acid derivatives decreases as the basicity of the leaving group increases. The basicity of the leaving group increases as

Cl– < RCOO– < RO–< NH2–

Secondly least stabilization by resonance due to ineffective overlapping between the 3p orbital of Cl and 2p orbital of carbon.