Which of the following best explains how catalysts increase the rate of chemical reactions?

• A. They provide additional reactant molecules.
• B. They increase the temperature of the reaction mixture.
• C. They increase the equilibrium constant of the reaction.
• D. They lower 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 increases the rate of a chemical reaction without being consumed in the process.
2. Recall that the rate of a chemical reaction depends on the activation energy, which is the minimum energy required for reactants to transform into products.
3. Recognize that catalysts work by providing an alternative reaction pathway with a lower activation energy, making it easier for reactant molecules to convert into products.
4. Note that catalysts do not change the temperature of the reaction mixture or the equilibrium constant; they only affect the speed at which equilibrium is reached.
5. Conclude that the best explanation for how catalysts increase reaction rates is that they lower the activation energy required for the reaction to proceed.