Question

What are the differences between order of reaction and molecularity of reaction?

Answer 1

Dear student,

The way in which order and molecularity of reaction varies is as follows:

1. DEFINITION: Order Sum of the exponents of the molar concentration(s) in the rate law expression. Molecularity The number of atoms, ions, molecules that must collide with one another simultaneously to result into a chemical reaction.
2. Order need not be a whole number. It can be fractional or zero. Molecularityis always a whole number.
3. Order can be determined experimentally only. Molecularity can be calculated by adding the no. of molecules in the slowest step (directly by looking at the balanced equation).
4. Order is applicable to simple + elementary reactions. Molecularity is applicable to simple reactions. No significance in determining molecularity of a complex reaction.
5. Order cannot be determined by looking at the stoichiometric coefficients. Molecularity can be determined by looking at the stoichiometric coefficients.