In the context of chemistry, what is a catalyst?

A catalyst is defined as a substance that increases the rate of a chemical reaction without undergoing any permanent chemical changes itself. This means that a catalyst facilitates the reaction process by lowering the activation energy, allowing the reactants to convert into products more efficiently. After the reaction occurs, the catalyst remains unchanged and is available to participate in additional reactions.

This characteristic is crucial for many industrial and biochemical processes, where the efficiency and speed of reactions can be greatly enhanced by the presence of a catalyst, making it vital in various applications ranging from manufacturing to biological systems. The other options do not accurately describe the nature of a catalyst; they either suggest opposite functions or describe other concepts in chemistry.