A number of chemical reactions occur around us in our day to day life. Some reactions happen within few seconds or even lesser and some other reactions take more time for completion. There are few more reactions which do not come to completion even after indefinite period of time. It will be fascinating to see that certain reactions of the above mentioned type comes to completion within a short period of time upon addition of a catalyst.

This type of substance added in a small amount to increase the rate of a reaction is called catalyst. The important thing that is to be kept in mind is the catalyst is recovered at the end of a reaction. The stud of the rate of a reaction in the presence of a catalyst is called catalysis.

When a small amount of catalyst is added, the activation energy of the reaction is reduced favouring the formation of product. This shows that the presence of a small amount of catalst will provide another path to the reaction which has a lower activation energy as shown in figure1