Question

What is the difference between order of a reaction and the molecularity of a reaction?

Answer 1

Order of a reaction	Molecularity of a reaction
It is the sum of the concentration terms on which the rate of reaction depends or sum ofthe exponents of the concentration in the law equation.	It is the number of molecules involved in the slowest step.
It may be fraction as well as zero also.	It is always a whole number
It can only be determined experimentally i.e., can not be calculated	It can be calculated by simply adding the molecules of the slowest step.