Does the presence of a catalyst alter the equilibrium constant of a reaction?

The presence of a catalyst does not change the equilibrium constant of a reaction. A catalyst functions by providing an alternative reaction pathway with a lower activation energy, which increases the rate at which equilibrium is reached for both the forward and reverse reactions. However, it does not favor either direction of the reaction—instead, it accelerates both equally.

The equilibrium constant is a ratio of the concentrations of products to the concentrations of reactants at equilibrium, and it is determined solely by the thermodynamics of the reaction, particularly the free energy changes associated with the conversion of reactants to products. Since a catalyst does not alter these thermodynamic properties, the equilibrium constant remains constant regardless of whether a catalyst is present or not. Thus, the correct understanding is that the presence of a catalyst facilitates reaching equilibrium more rapidly without altering the position of the equilibrium itself or the value of the equilibrium constant.