Changing the concentration of reactants and products in a chemical reaction can have different effects on the equilibrium constant K and the reaction rate.1. Effect on the equilibrium constant K : The equilibrium constant K is a measure of the relative concentrations of reactants and products at equilibrium. It is important to note that the equilibrium constant is only affected by temperature changes and not by changes in the concentrations of reactants or products. Therefore, changing the concentration of reactants or products will not affect the equilibrium constant K of the reaction.2. Effect on the reaction rate: The reaction rate is the speed at which a chemical reaction proceeds. It depends on several factors, including the concentration of reactants and products. According to the law of mass action, the rate of a reaction is directly proportional to the product of the concentrations of the reactants, each raised to the power of their stoichiometric coefficients in the balanced chemical equation.When the concentration of reactants increases, the reaction rate generally increases because there are more reactant molecules available to collide and react with each other. Conversely, when the concentration of reactants decreases, the reaction rate generally decreases.Similarly, when the concentration of products increases, the reverse reaction rate i.e., the rate at which products are converted back into reactants generally increases, while a decrease in product concentration will lead to a decrease in the reverse reaction rate.In summary, changing the concentration of reactants and products can affect the reaction rate but not the equilibrium constant K of a chemical reaction.