Final answer:
The overall order of the reaction with the rate law Rate = k[X]^2[Y] is third-order, determined by summing the exponents of the concentration terms (which are 2 for [X] and 1 for [Y]).
Step-by-step explanation:
The overall order of the reaction given by the rate law Rate = k[X]^2[Y] is determined by adding the exponents of the concentration terms in the rate equation. In this case, the reaction order with respect to [X] is 2, because [X] is squared, and the reaction order with respect to [Y] is 1, since [Y] appears to the first power. Therefore, the overall reaction order is 2 + 1, which equals 3. This means the reaction is third-order overall.