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?