What happens to the activation energy of a reaction when a catalyst is used?

• A. The activation energy increases
• B. The activation energy stays the same
• C. The activation energy decreases
• D. The activation energy is eliminated

Answer: (C)

When a catalyst is introduced to a chemical reaction, it provides an alternative pathway for the reaction to proceed, which has a lower activation energy compared to the uncatalyzed reaction. This means that the energy barrier that must be overcome for the reactants to transition to products is reduced, allowing the reaction to occur more readily and at a faster rate.

The function of a catalyst is to facilitate the reaction without being consumed in the process, so while it lowers the required activation energy, it does not alter the overall energy difference between the reactants and products. Therefore, the correct choice reflects that the activation energy decreases when a catalyst is present.