Mechanism of a hypothetical reaction X 2 + Y 2 → 2 XY is given below: (i) X 2 → X + X   fast (ii) X + Y 2 ⇌ XY + Y   slow (iii) X + Y → XY   fast The overall order of the reaction will be

Step-by-step solution

The solution of this question is given by assuming step ( i ) to be reversible which is not given in question Overall   rate   =   Rate   of   slowest   step   ( ii ) = k X   Y 2 ...... ( i ) K = rate constant of step ( ii ) Assuming step ( i ) to be reversible, its equilibrium constant, k e q = X 2 X 2     ⇒       X = k e q 1 2   X 2 1 2 ..... ( ii ) Put ( ii ) in ( i ) Rate = k k e q 1 2   X 2 1 2   Y 2 Overall order = 1 2 + 1 =