Increasing the concentration of reactants in a chemical reaction generally leads to an increase in the reaction rate. This is because a higher concentration of reactants results in a higher frequency of collisions between the reacting molecules, which in turn increases the probability of successful collisions that lead to the formation of products.The effect of concentration on the reaction rate can be described by the rate law, which is an equation that relates the rate of a reaction to the concentrations of the reactants. The rate law typically takes the form: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, respectively. The reaction orders m and n indicate how the reaction rate is affected by the concentration of each reactant. For example, if m = 1, the reaction rate is directly proportional to the concentration of reactant A.As for the reaction mechanism, increasing the concentration of reactants does not usually change the mechanism itself. The reaction mechanism is a series of elementary steps that describe the sequence of bond-breaking and bond-forming events that occur during the conversion of reactants to products. However, increasing the concentration of reactants can affect the relative rates of the individual steps in the mechanism, which may lead to changes in the overall reaction rate and the distribution of intermediate species.In summary, increasing the concentration of reactants typically increases the reaction rate due to more frequent and successful molecular collisions, but it does not generally change the underlying reaction mechanism.