What role do catalysts play in chemical reactions?

Catalysts play a crucial role in chemical reactions by providing an alternative pathway for the reaction to occur, which lowers the activation energy barrier. This means that reactants can convert to products more easily and quickly when a catalyst is present. While catalysts may temporarily interact with the reactants during the reaction process, they do not undergo permanent changes and are regenerated at the end of the reaction. As a result, they can be used repeatedly without being consumed, which is why option C is the correct answer.

The function of catalysts can be particularly useful in industrial processes where increasing the rate of a reaction can lead to greater efficiency and productivity. Their ability to facilitate reactions without being depleted helps in maintaining more constant conditions in a chemical system.

Other options highlight certain misconceptions about the nature of catalysts. For instance, the idea that they are consumed during the reaction is incorrect, as catalysts are not permanently altered and remain available for future reactions. The statement regarding catalysts only working at high temperatures is misleading since many catalysts operate at a range of temperatures, and their effectiveness is not solely dependent on high temperatures. Lastly, increasing the activation energy required contradicts the fundamental property of catalysts, which is to lower the activation energy, thus making the reaction occur more readily.