K1 and K2 are equilibrium constant for reactions (1) and (2) N2(g) + O2(g) 2 NO (g) ....... (1) NO(g) N (g) O (g) .........(2) (a) K K

Reaction (2) is a reverse reaction of reaction (1) and the reaction (2) is also half of the reaction (1). Thus, the rate constant can be given as 2 2 1 1 2 1 K = K 1 K = K >> >> Hence, the correct answer is option (a)