Which of the following best describes the function of a catalyst in a chemical reaction?

• A. It increases the rate of the reaction by lowering the activation energy.
• B. It increases the equilibrium constant of the reaction.
• C. It is consumed during the reaction and becomes part of the products.
• D. It changes the enthalpy change (ΔH) of the reaction.

Answer: (A)

Verified step by step guidance

1. Understand that a catalyst is a substance that affects the rate of a chemical reaction without being consumed in the process.
2. Recall that the activation energy is the minimum energy required for reactants to transform into products during a reaction.
3. Recognize that a catalyst works by providing an alternative reaction pathway with a lower activation energy, which increases the reaction rate.
4. Note that a catalyst does not change the equilibrium constant or the overall enthalpy change (ΔH) of the reaction; it only helps the system reach equilibrium faster.
5. Conclude that the best description of a catalyst's function is that it increases the rate of the reaction by lowering the activation energy.