What is the role of a catalyst in a chemical reaction?

The role of a catalyst in a chemical reaction is to increase the reaction rate without being consumed in the process. Catalysts achieve this by providing an alternative pathway for the reaction that has a lower activation energy compared to the uncatalyzed reaction. This means that more molecules have enough energy to undergo the reaction at a given temperature, leading to an increased rate of product formation.

While the choice that mentions decreasing the activation energy is related to the function of a catalyst, it is not as comprehensive as stating that it increases the reaction rate without being consumed. Importantly, catalysts do not alter the overall equilibrium position of a reaction; they facilitate the approach to equilibrium but do not change the concentrations of reactants and products at equilibrium. Furthermore, since a catalyst is not consumed during the reaction, it can be used repeatedly in multiple reaction cycles, which is a defining characteristic of catalysts.