CBSE Class 12 Chemistry Notes: Chemical Kinetics – Half Life

Half life of first order:

Time required to consume the half of initial concentration of reactant is called half life period.

At half life time:

Thus half life period is independent of initial concentration.

Unit of rate constant is time^-1.

Reciprocal of rate const. (half life) is average life.

After ‘n’ half times the concentration A= A₀/2ⁿ

Examples:

T₇₅ = 2 ´ t₅₀. i.e. time  taken to complete 75 % of reaction is twice that of half life time.

Examples of First Order Reactions:

Half life of Nth Order Reaction:
For n^th order reaction the mathematical expression:

Chemical Kinetics of population growth:

Class 12 Chemistry Chemical Kinetics All Topics Notes CBSE Class 12 Chemistry All Chapters Notes