For the reaction A+B→C, it is found that doubling the concentration of A increases the rate by 4 times, and doubling the concentration of B doubles the reaction rate. What is the overall order of the reaction?

A+B→COn doubling the concentration of A rate of reaction increases by four times. Rate ∝[A]2However on doubling the concentration of B, rate of reaction increases two times. Rate ∝[B]Thus, overall order of reaction = 2 + 1 = 3.