What is the equation used to calculate the mean rate of a reaction based on reactants?

The mean rate of a reaction is a measure of how quickly a reactant is consumed or how quickly a product is formed over a specific period of time. The correct formula for calculating the mean rate of a reaction in terms of reactants is based on the quantity of reactants used divided by the time taken for the reaction to proceed. This relationship allows one to quantify the speed of the reaction in relation to how much of the reactant has been utilized.

Using the quantity of reactant used in the calculation highlights the consumption aspect of reactions, which is crucial for understanding reaction kinetics. This approach provides a direct representation of how fast the reactants are transformed into products during the overall reaction, making it a fundamental concept in chemical kinetics.

In contrast, other formulations do not directly address the rate concerning how reactants decrease or how immediately the reaction kinetics are being measured, which is why they do not fit the definition required for the mean rate of a reaction based on reactants.