Question

What does ‘m’ stand for in the rate law equation?
A) Reaction order
B) Concentration of reactant
C) Concentration of product
D) Number of moles
E) Rate

Answer 1

The main approach for this answer is that the rate law is dependent on the power dependence of the rate on the concentration of individual reactant. This definition gives the correct answer.

Complete Solution :
In the lower classes of chemistry, we have studied about the concepts of rate of reaction and the dependence of reaction rates on several factors in the physical chemistry part.

Let us now consider the rate of reaction and its dependence which gives the rate law:
- Rate of a reaction is the speed at which the chemical reaction proceeds from reactant to the product side.
- Rate of a reaction depends on the concentration of the reactants as well as number of moles of the reactants used which determines the total order of the reaction.
- Rate law is the mathematical expression given to denote the total number of moles of reactants and products that are participating in the reaction with its concentration terms.

Consider a general reaction for a single molecule giving products as:
$mA\xrightarrow{{}}products$
Now, rate law for this reaction is given by:
$Rate=k{{[A]}^{m}}$
where, k is the rate constant for a given reaction
Here, m is nothing but the quantity that denotes order of reaction that is the power dependence of the rate of concentration of each reactant.
So, the correct answer is “Option A”.

Note: The rate law is not dependent on only the letter ‘m’ but instead of ‘m’ even ‘n’ can be used and for the reaction involving more than one reactant various other alphabets can be used and do not be confused.