How does a catalyst increase the rate of a chemical reaction?

• A. It provides additional reactant molecules.
• B. It changes the equilibrium position of the reaction.
• C. It lowers the activation energy required for the reaction to occur.
• D. It increases the temperature of the reactants.

Answer: (C)

Verified step by step guidance

1. Understand that the rate of a chemical reaction depends on how quickly reactant molecules can overcome the energy barrier known as the activation energy (E_a).
2. Recognize that a catalyst works by providing an alternative reaction pathway with a lower activation energy, which means more molecules have enough energy to react at a given temperature.
3. Note that a catalyst does not change the equilibrium position of the reaction; it only helps the system reach equilibrium faster by speeding up both the forward and reverse reactions.
4. Realize that a catalyst does not increase the temperature or the number of reactant molecules; instead, it affects the energy landscape of the reaction.
5. Summarize that by lowering the activation energy, a catalyst increases the reaction rate without being consumed in the process.