What is heterogeneous catalysis ? Give an example.

Explanation

At catalytic process in which the reactants and the catalyst are in different phases is known as heterogeneous catalysis.
Example (1) : Oxidation of sulphur dioxide to sulphur trioxide in presence in platinum catalyst.
`2SO_(2)(g) + O_(2)(g) overset(Pt(s))rarr 2SO_(3)(g)`
Example (2) : Combination of hydrogen and nitrogen to form ammonia.
`N_(2)(g) + 3H_(2)(g) overset(Fe(s))rarr 2NH_(3)(g)`
Example (3) : Hydrogenation of vegetable oil.
Vegetable oil `(l+) + H_(2)(g) overset(Ni(s))rarr` Vanaspathi (s).