What is catalysis ? How is catalysis classified ? Give two examples for each type of catalysis.

Explanation

Substances which accelerate the rate of a slow chemical reaction but whose chemical nature and mass remain unchanged after the reaction are known as catalysts and the phenomenon is known as catalysis.
Catalysis is mainly two types.
1) Homogeneous catalysis: When the reactants and the catalyst are in the same phase i.e., either liquid or gas the process is said to be homogeneous catalysis. e.g: i) `2SO_(2)(g)+O_(2)(g) overset(NO(g)) to 2SO_(3)(g)`
Reactants `SO_(2) and O_(2)` and the catlyst NO are all gases and in the same phase
(ii) `CH_(3)COOC_(3)(l)+H_(2)O(l) overset(HCl(l)) to CH_(3)COOH(aq)+C_(2)H_(5)OH)(aq)`
The reastants and catalysts are in the same liquid phase.
2) Heterogeneous catalysis: The catalytic process in which the reactants and the catalyst are in different phases is known as heterogeneous catalysis..
`(i) 2SO_(2)(g)+O_(2)(g) overset(Pt(s)) to 2SO_(3)(g)`
The reactants are in gaseous state while that catalyst is solid.
`N_(2)+3H_(2) overset(Fe(s)) hArr 2NH_(3)(g)`
Reactants are gases, catalyst is:solid.