Mechanism of a hypothetical reaction X Y XY -> is given below: (i) fast X X X (ii) slow -> X Y XY Y (iii) fast X Y XY -> The overall order of the reaction will be; (NEET 2017)

The overall reaction rate depends on the rate of the slowest step. i.e., Overall rate = Rate of slowest step (ii) = k[X][Y2] ... (1) k = rate constant Step (i) equilibrium constant, 2 2 2 2 ; >> eq eq X K X K X X 1 1 2 2 2 eq X K X … (2) From eq (1) and (2) Rate = 1 1 2 2 2 2 eq kK X Y Overall order = 1 3 1 1.5 2 2