Changing the concentration of one reactant in a chemical reaction can have significant effects on both the initial rate and the final yield of the reaction. The relationship between the concentration of reactants and the rate of reaction is described by the rate law, which is determined by the reaction mechanism.1. Effect on the initial rate:The initial rate of a reaction is typically directly proportional to the concentration of the reactants raised to some power, as described by the rate law:Rate = k[A]^m[B]^nwhere Rate is the initial rate of the reaction, k is the rate constant, [A] and [B] are the concentrations of the reactants, and m and n are the reaction orders with respect to A and B, respectively.When the concentration of one reactant is increased, the initial rate of the reaction will generally increase as well. The extent to which the rate increases depends on the reaction order with respect to that reactant. For example, if the reaction is first-order with respect to reactant A, doubling the concentration of A will double the initial rate. If the reaction is second-order with respect to A, doubling the concentration of A will quadruple the initial rate.2. Effect on the final yield:The final yield of a reaction is the amount of product formed at equilibrium. Changing the concentration of one reactant can affect the position of the equilibrium, which in turn affects the final yield. According to Le Chatelier's principle, if the concentration of a reactant is increased, the equilibrium will shift in the direction that consumes the added reactant, potentially leading to a higher final yield of the product. However, this is not always the case, as the effect on the final yield depends on the specific reaction and the stoichiometry of the balanced equation.3. Relationship to the reaction mechanism:The reaction mechanism is the step-by-step sequence of elementary reactions by which the overall chemical reaction occurs. The rate law and reaction orders are determined by the slowest step in the mechanism, known as the rate-determining step. By studying the effect of changing the concentration of one reactant on the initial rate and final yield, chemists can gain insights into the reaction mechanism and the rate-determining step, which can help in optimizing reaction conditions and designing more efficient chemical processes.