Why might a catalyst increase the rate of a reaction?

A catalyst increases the rate of a reaction by providing an alternative pathway with a lower activation energy. This means that the energy barrier that must be overcome for the reactants to convert into products is reduced. As a result, more particles have the necessary energy to undergo the reaction at a given temperature, which leads to an increase in the reaction rate.

Catalysts achieve this without being consumed in the reaction, allowing them to be used repeatedly. The lower activation energy allows the reaction to proceed more easily and quickly, which is why catalysts are extremely valuable in both industrial processes and biological systems where enzymes act as biological catalysts.

The other options, while related to chemical processes, do not accurately describe the function of a catalyst. For example, increasing the temperature of the reactants can also increase the reaction rate but is not a catalytic process. Similarly, adding more reactants can increase the concentration, potentially speeding up the reaction due to more frequent collisions, but does not involve a catalyst. Changing the physical state of the reactants may influence the reaction as well; however, this does not fundamentally represent the role of a catalyst in lowering activation energy.