The effect of changing the concentration of reactants on the rate of a reaction depends on the reaction mechanism, whether it is a single-step or multi-step mechanism.For a single-step mechanism, the rate of the reaction is directly proportional to the concentration of the reactants. This can be represented by the rate law equation:Rate = k[A]^m[B]^nwhere Rate is the reaction rate, k is the rate constant, [A] and [B] are the concentrations of reactants A and B, and m and n are the reaction orders with respect to A and B. In a single-step mechanism, the reaction orders m and n are equal to the stoichiometric coefficients of the reactants in the balanced chemical equation. Therefore, increasing the concentration of a reactant will lead to an increase in the reaction rate.For a multi-step mechanism, the overall reaction rate is determined by the slowest step, also known as the rate-determining step. The rate law for a multi-step reaction is still represented by the same equation:Rate = k[A]^m[B]^nHowever, the reaction orders m and n may not necessarily be equal to the stoichiometric coefficients of the reactants in the balanced chemical equation. Instead, they depend on the rate-determining step and the mechanism of the reaction. In some cases, increasing the concentration of a reactant may have a significant effect on the reaction rate, while in other cases, it may have little to no effect.In summary, changing the concentration of reactants in a single-step reaction will directly affect the reaction rate according to the rate law equation. In a multi-step reaction, the effect of changing reactant concentrations on the reaction rate depends on the rate-determining step and the reaction mechanism.