Final answer:
The reaction has a second-order dependence on NO and first-order on H2, resulting in a third-order overall reaction rate.
Step-by-step explanation:
The reaction 2NO(g) + H₂(g) → N₂(g) + 2 H₂O(g) has a rate law expressed as rate = k[NO]²[H₂]. The order with respect to NO (nitrogen monoxide) is 2 since the concentration of NO is squared in the rate law, indicating that the rate of reaction is proportional to the square of the concentration of NO. The order with respect to H₂ (hydrogen) is 1 because the concentration of H₂ is to the first power. Hence, the overall order of the reaction is the sum of the individual orders, which is 2 + 1 = 3. The overall order of the reaction is third-order.