Question

Relation between molecularity and order of reaction

Answer 1

Molecularity : It is the number of reacting species undergoing simultaneous collision in elementary or simple reaction.

Order : it is the sum of power of the concentration on which the rate of reaction actually depends or it is the sum of exponent of concentration in the rate law equation.

Generally, order of Elementary reaction is equal to its molecularity. However, if the condition of pressure or concentration are changed the order may or may not be equal to the molecularity because in that case reaction will not take place in one step that is not remain in elementary reaction but it become a complex reaction.

For example, A Uni molecular reaction is a first order at high pressure but at low pressure it become second order reaction.!