The branch of chemistry, which deals with the rate of chemical reactions. the factors affecting the rate of reactions and the mechanism of the reaction. is called chemical kinetics.
Chemical Reactions on the Basis of Rate of Reaction
1. Fast/instantaneous reactions Chemical reaction that completes in less than Ips (10- 12 s) time, IS known as a fast reaction. It IS practically impossible to measure the speed of such reactions, e.g., ionic reactions. organic substitution reactions.
2. Slow reactions Chemical reactions that complete in a long time from some minutes to some years are called slow reactions. e.g., rusting of iron. transformation of diamond, etc.
3. Moderately slow reactions Chemical reactions which are intermediate between slow and fast reactions are called moderately slow reactions.