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

The primary role of a catalyst in a chemical reaction is to increase the rate at which the reaction occurs without being consumed in the process. A catalyst achieves this by providing an alternative reaction pathway that has a lower activation energy compared to the uncatalyzed reaction. This effectively speeds up the reaction by allowing more molecules to have sufficient energy to participate, thereby increasing the reaction rate.

While the second option mentioned—decreasing the activation energy—is also true, it is essentially a specific description of how a catalyst operates, rather than its overall role in the reaction context. The key aspect of a catalyst is its ability to facilitate and accelerate the reaction process while remaining unchanged after the reaction is complete. This makes it a crucial component in many industrial and biological processes, enabling reactions that would otherwise occur very slowly or not at all under certain conditions.