Question

In a chemical reaction, what substance is considered a catalyst, and why?

A: The substance that is consumed the fastest is a catalyst because it speeds up the reaction.
B: The substance that is produced the fastest is a catalyst because it slows down the reaction.
C: The substance that increases the rate of the chemical reaction is a catalyst because it remains unchanged during the reaction.
D: The substance that decreases the rate of the chemical reaction is a catalyst because it is consumed during the reaction."

Answer 1

A catalyst facilitates a reaction by providing an alternative pathway with lower activation energy. It is not consumed and is regenerated, allowing it to participate in multiple reaction cycles without undergoing a net change. The correct answer is C: The substance that increases the rate of the chemical reaction is a catalyst because it remains unchanged during the reaction.

Step-by-step explanation:

A catalyst is a substance that facilitates a chemical reaction by providing an alternative reaction pathway with a lower activation energy. Importantly, a catalyst is not consumed in the reaction; it undergoes no net change in composition, and at the end of the reaction, it is regenerated. This unique feature allows the catalyst to participate in multiple reaction cycles.

Options A and B incorrectly associate the speed of consumption or production with being a catalyst, which is not accurate. Option D incorrectly suggests that a substance decreasing the reaction rate is a catalyst, which is inconsistent with the definition of a catalyst. The defining characteristic of a catalyst is its ability to increase the rate of a reaction while remaining unchanged in the process.