Decide which of the following statements about catalysts are true. If the statement is false, explain why.

(a) A heterogeneous catalyst works by binding one or more of the molecules undergoing reaction to the surface of the catalyst.

(b) Enzymes are naturally occurring proteins that serve as catalysts in biological systems.

(c) The equilibrium constant for a reaction is greater in the presence of a catalyst.

(d) A catalyst changes the pathway of a reaction in such a way that the reaction becomes more exothermic.