What are the types of systems? Explain give one example each? 

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 can be broadly divided into two groups.
I) Homogeneous catalysis : When the reactants and the catalyst are in the same phase i.e. either in liquid or in gas phase, the process is said to be homogeneous catalysis.
Example :
Oxidation of `SO_(2) ` to `SO_(3)` in the presence of oxides of nitrogen
` 2SO_(2) (g) + O_(2) (g) overset (NO(g))to 2 SO_(3)(g)`
`SO_(2) , O_(2)` and the catalyst NO are all gases and are in same phase
II) Heterogeneous catalysis: The catalytic process in which the reactants and the catalyst are in different phases is known as heterogeneous catalysis
Example :
Oxidation of ` SO_(2) ` to ` SO_(3)` in the presence of Pt.
` 2SO_(2) (g) + O_(2) ( g) overset(Pt (s))to 2SO_(3) (g)`