What is the effect of catalyst on :

(i) Gibbs energy (ΔG) and

(ii) activation energy of a reaction?

A catalyst is a substance which alters the rate of a reaction without itself undergoing any permanent chemical change.

(i) Gibbs energy (ΔG)

Gibbs energy is a state function. It depends on enthalpy and entropy which depend on the initial and final positions of substance irrespective of the path it follows. The catalyst can help in making a reaction occur fast or reach equilibrium fast. It doesn’t alter reactants, products or equilibrium constant. So, it doesn’t change enthalpy or entropy. So, Gibbs energy doesn’t change due to the addition of catalyst.

(ii) the activation energy of a reaction?

A catalyst helps in attaining equilibrium earlier. It reduces the potential barrier and provides an alternate pathway or reaction mechanism by reducing the activation energy between reactants and products, due to which equilibrium is reached faster. It alters the rate of reaction.