The chemical substance due to the presence of which rate of chemical reaction is increased or decreased but does not take part in chemical reaction itself is called catalyst and the process is called catalysis. The chemical substance due to the presence of which rate of chemical reaction is increased or decreased but does not take part in chemical reaction itself is called catalyst and the process is called catalysis. Jons Jacob Berzelius discovered the chemical phenomena of catalysis in 1835 and he confirmed that the rate of reaction can be affected by the presence of any chemical substance.
Example: If KClO3 be heated at extremely high temperature, the released oxygen gas emerges very slowly, but if in small amount MnO2 be mixed up then even at moderate temperature oxygen gas is released fastly.
Types of catalysis
There are two types of catalysis: (i) Homogeneous catalysis; (ii) Heterogeneous catalysis
In homogeneous catalysis, catalyst and reactants are in same physical state, while in heterogeneous catalysis, catalyst and reactants both are in different physical states.
Types of catalyst
There are various types of catalyst but usually there are four types which are significant and important-
(i) Positive catalyst: The catalyst which activates the rate of reaction is called positive catalyst.
(ii) Negative catalyst: The catalyst which deactivates the rate of reaction is called negative catalyst.
(iii) Auto catalyst: When any product forms during any chemical- reaction acts like the catalyst for the same chemical reaction then it is called auto catalyst.
(iv) Induced catalyst: When the product of any chemical reaction acts like the catalyst of any other chemical reaction then it is called induced catalyst.
The compressed condensed nitrogenous substance found to be in microbes or micro organism through which the process of fermentation is performed is called enzyme. This is present in the cells of every living creature and it is responsible and fully accountable for the various metabolic activities taking place in the living beings.
Enzymes are sometime called bio chemical catalysts. Thus enzymes are condensed substances like protein and these act like contact catalyst and provoke the decomposition process to complex high organic substance into simpler substance. The enzymes are very exclusive and they perform single activity of a time. The activities of enzymes are abruptly diminished or vanished in the presence of any toxic substance at high temperature. At ordinary temperature enzyme functions optimally.