Question

How does a catalyst work? using these options...

Answer 1

Answer: D) By decreasing the activation energy of a reaction

A catalyst is a substance that speed up the rate of chemical reaction without affecting the product of the reaction. They only affect the rate of reaction not the yield of reaction.

Catalyst provide an alternative reaction pathway that has lower activation energy  than that of uncatalysed reaction. It increases the frequency of collision and because of these greater collision which lowers the activation energy of the reaction.

Answer 2

D is the answer (activation energy)