Chemical Kinetics

The branch of chemistry, which deals with the rate of chemical reactions, the factors affecting the rate of reactions and the mechanism of the reactions, is called chemical kinetics.

We need to find out,

a. the feasibility of a chemical reaction which can be predicted by thermodynamics (A reaction with ΔG < 0, at constant temperature and pressure is feasible);

b. extent to which a reaction will proceed can be determined from chemical equilibrium;

c. speed of a reaction i.e., time taken by a reaction to reach equilibrium.

Classification of chemical reactions on the basis of rate of reaction

Fast/instantaneous reactions

Chemical reaction which completes in less than 1 ps (10^-12 s) time is known as fast reaction. It is practically impossible to measure the speed of such reactions, e.g., ionic reactions, organic substitution reactions.

Slow reactions

Chemical reactions which complete in a long time from some minutes to some years are called slow reactions, e.g., rusting of iron, transformation of carbon into diamond etc.

Moderately slow reactions

Chemical reactions which are intermediate between slow and fast reactions are called moderately slow reactions.