Which statement best describes the amount of catalyst that remains at the end of a chemical reaction?

• A. The catalyst is converted into a product and removed from the reaction mixture.
• B. The catalyst is completely consumed during the reaction.
• C. The catalyst increases in amount due to the reaction.
• D. The catalyst remains unchanged and is present in the same amount as at the start.

Answer: (D)

Verified step by step guidance

1. Understand the role of a catalyst in a chemical reaction: a catalyst speeds up the reaction without being consumed or permanently changed.
2. Recall that a catalyst participates in the reaction mechanism by lowering the activation energy but is regenerated by the end of the reaction.
3. Recognize that because the catalyst is regenerated, its amount remains the same before and after the reaction.
4. Eliminate options that suggest the catalyst is consumed, converted into products, or increases in amount, as these contradict the fundamental definition of a catalyst.
5. Conclude that the correct statement is that the catalyst remains unchanged and is present in the same amount as at the start of the reaction.