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

A catalyst plays a crucial role in chemical reactions by decreasing the activation energy required for the reaction to occur. Activation energy is the minimum amount of energy needed for reactants to undergo a transformation into products. By lowering this energy barrier, catalysts allow reactions to proceed more readily and at lower temperatures, making them essential in various biological processes and industrial applications.

Catalysts work by providing an alternative reaction pathway that requires less energy, thereby speeding up the rate of the reaction without being consumed in the process. This means that after facilitating the reaction, the catalyst can be reused repeatedly, maintaining its availability for future reactions.

The other options do not accurately describe the function of a catalyst: it does not increase the activation energy, alter the products formed in a way that changes the reaction itself, or prevent the reaction from occurring. Instead, a catalyst specifically enhances the reaction by making it easier for the reactants to convert into products.