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

• A. It lowers the activation energy, increasing the reaction rate without being consumed.
• B. It increases the activation energy, making the reaction slower.
• C. It is consumed during the reaction and becomes part of the products.
• D. It changes the equilibrium position 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 because the catalyst is not consumed, it can be used repeatedly and does not change the overall equilibrium position of the reaction.
5. Conclude that the best description of how a catalyst works is that it lowers the activation energy, increasing the reaction rate without being consumed.