Question

select the correct answer. which statement is true about a catalyst? a. a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.

Explanation:

• Option A: A catalyst actually increases (or speeds up) the reaction rate, not decreases it. So A is false.
• Option B: A catalyst is not consumed in a chemical reaction; it remains chemically unchanged and can be reused. So B is false.
• Option C: By definition, a catalyst functions by lowering the activation energy of a reaction, which allows the reaction to proceed more quickly. This is a core property of catalysts. So C is true.
• Option D: A catalyst does not affect the concentration of reactants. Reactant concentration is related to the amount of reactant present, and a catalyst doesn't change that. So D is false.

Answer:

C. A catalyst lowers the activation energy of a reaction.