How does a catalyst affect a chemical reaction?

• A. It changes the equilibrium position of the reaction.
• B. It increases the activation energy, slowing down the reaction.
• C. It is consumed during the reaction and becomes part of the products.
• D. It lowers the activation energy, increasing the reaction rate without being consumed.

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 activation energy (\[E_a\]) 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 allows more reactant molecules to have enough energy to react at a given temperature.
4. Note that because the catalyst is not consumed, it does not change the equilibrium position of the reaction; it only helps the system reach equilibrium faster.
5. Summarize that the key effect of a catalyst is to lower the activation energy, thereby increasing the reaction rate without altering the reactants or products.