Catalyst

                          Catalyst

In 1836 Bergillius absorbe that there are some substances which increases the rate of reaction without changing themselves. 

  

A catalyst is defined as a substance which change the rate of reaction without undergoing any change themselves and can be recovered. The phenomina of increasing the rate of reaction with the help of catalyst is called Catalysis. 

Catalyst is of two types-   

1. Positive Catalyst

 2. Negative Catalyst

1.Positive catalyst:-   the catalyst which increase the rate of reaction is called positive catalyst and the process is called positive catalysis. 

Example- 

      2kclo3 —––— 2kcl + 3O2

      4Hcl + 02—— 2H2O +2cl2

2. Negative catalyst:- the negative catalyst which decreases the rate of reactions is called negative catalyst and the phenomina is called Negative Catalysis. 

Example-

4CHcl3+302——4COcl2+                                      2H2O+2cl2