what is the effect of using catalyst in a reaction on

(i) activation energy

(ii) gibbs energy of a reaction

The effect of catalyst is as follow:

(a) effect of catalyst on activation energy :- The activation energy is the minimum energy required to convert a reactant into product. When catalyst is added to the reaction then it lowers the activation energy of reactants and hence it increases the rate of reaction increases.

(b) Effect of catalyst on Gibbs free energy :- there is no effect of catalyst on gibbs free energy :-

This can be explained as follow :

As ΔG =  ΔH- T ΔS

Since on adding catalyst, enthalpy, entropy and temperature remain same therefore there is no effect on Gibbs free energy.