Question 9

Consider the following reaction,

$2H_2(g) + 2NO(g) \to N_2(g) + 2H_2O(g)$

which follows the mechanism given below:

$2NO(g) \xrightleftharpoons[k_{-1}]{k_1} N_2O_2(g) \quad (\text{fast equilibrium})$

$N_2O_2(g) + H_2(g) \xrightarrow{k_2} N_2O(g) + H_2O(g) \quad (\text{slow reaction})$

$N_2O(g) + H_2(g) \xrightarrow{k_3} N_2(g) + H_2O(g) \quad (\text{fast reaction})$

The order of the reaction is ______.