**Stoichiometric coefficient:**

The number of molecules of a reactant taking part in a reaction is known as Stoichiometric coefficient.

For example:

Consider the following equation:

aA + bB ⇌ cC + dD

In this equation, a, b, c and d are called as Stoichiometric coefficients of the A, B, C and D respectively.

During calculation of rate of reaction why do we take reciprocal of stoichiometric coefficient? Why do these taken proportionally?