Question

What is the difference between homogeneous and heterogeneous catalysis?

Answer 1

Sr. No.	Homogeneous catalysis	Heterogeneous catalysis
1.	In a catalysed reaction the reactants, products and catalyst are present in the same phase.	In a reaction, the catalyst is present in a different phase. i.e., the catalyst is not present in the same phase as that of reactants and products.
2.	For example, \[\ce{2SO2_{(g)} + O2_{(g)} ->[NO_{(g)}] 2SO3_{(g)}}\] Hence NO act as catalyst.	For example, \[\ce{2SO2_{(g)} + O2_{(g)} ->[Pt_{(s)}] 2SO3_{(g)}}\] Hence Pt(s) act as catalyst.
3.	Homogeneous catalysis is explained by intermediate compound formation theory.	Heterogeneous catalysis is explained by adsorption theory.