A hypothetical reaction, A 2 + B 2 → 2 A B follows the mechanism as given below A 2 ⇌ A + A (Fast) A + B 2 → A B + B (slow) A + B → A B (Fast) The order of the overall reaction is

Step-by-step solution

r = K [ A ] [ B 2 ] and K c = [ A ] [ A ] [ A 2 ] or [ A ] = K c 1 / 2 [ A 2 ] 1 / 2 Thus, r = K . K c 1 / 2 [ A 2 ] 1 / 2 [ B 2 ] Let K . K c 1 / 2 = K ' so r = K ' [ A 2 ] 1 / 2 [ B 2 ] Hence order is 3/2.