Why reactions having molecularity are less observed ?

Explanation

### Step-by-Step Solution:

1. **Definition of Molecularity**:
Molecularity refers to the number of reactant molecules that must collide simultaneously to produce a reaction. It is determined by the stoichiometry of the reaction.

2. **Example of Molecularity**:
Consider a reaction where two reactants A and B combine to form a product. The reaction can be represented as:
\[
...