The equilibrium constant K of a chemical reaction is a measure of the extent to which a reaction proceeds to completion. It is important to note that the equilibrium constant is not affected by the initial concentrations of the reactants or products. However, the position of the equilibrium i.e., the concentrations of reactants and products at equilibrium can be affected by the initial concentrations of the reactants.The equilibrium constant K is defined as the ratio of the concentrations of products to the concentrations of reactants, each raised to the power of their stoichiometric coefficients in the balanced chemical equation. For a general reaction:aA + bB cC + dDThe equilibrium constant expression is:K = [C]^c [D]^d / [A]รข [B]^b where [A], [B], [C], and [D] represent the molar concentrations of the species at equilibrium.Now, let's consider the effect of varying the initial concentrations of reactants on the position of the equilibrium:1. If the initial concentration of a reactant is increased, the system will shift towards the products to re-establish equilibrium. This will result in an increase in the concentration of products and a decrease in the concentration of reactants at equilibrium. However, the value of the equilibrium constant K will remain the same, as it is only dependent on temperature.2. If the initial concentration of a reactant is decreased, the system will shift towards the reactants to re-establish equilibrium. This will result in a decrease in the concentration of products and an increase in the concentration of reactants at equilibrium. Again, the value of the equilibrium constant K will remain the same.In summary, the variation of reactant concentration affects the position of the equilibrium, but it does not affect the equilibrium constant K of a chemical reaction. The equilibrium constant is only affected by changes in temperature.