Which statement best explains the role of a

catalyst in a chemical reaction?

(1) A catalyst is added as an additional reactant

and is consumed but not regenerated.

(2) A catalyst limits the amount of reactants used.

(3) A catalyst changes the kinds of products produced.

(4) A catalyst provides an alternate reaction pathway

that requires less activation energy.

Verified Answer :

The answer is (4). If you look at a Maxwell-Boltzmann energy curve, you will see that lowering the activation energy will increase the proportion of molecules with sufficient energy for a successful reaction collision. Therefore, a reaction with lower activation energy will proceed more quickly. Often, this lower activation energy is obtained by another mechanistic pathway. Catalysts increase reaction speed through these two basic mechanisms.