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

• A. It increases the equilibrium constant of the reaction.
• B. It raises the temperature of the reaction mixture.
• C. It is consumed during the reaction and becomes part of the products.
• D. It lowers the activation energy required for the reaction to proceed.

Answer: (D)

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 equilibrium constant (\(K\)) depends only on the thermodynamics of the reaction (free energy change) and is not changed by the presence of a catalyst.
3. Recognize that a catalyst does not change the temperature of the reaction mixture; temperature is an external condition.
4. Know that a catalyst is not consumed or permanently altered during the reaction, so it does not become part of the products.
5. Identify that the primary role of a catalyst is to lower the activation energy (\(E_a\)) required for the reaction to proceed, thereby increasing the reaction rate.