Question

The unit of rate and rate constant are same for a:
A. Zero Order Reaction
B. First Order Reaction
C. Second Order Reaction
D. Third Order Reaction

Answer 1

Hint: According to the Rate Law, the rate of reaction is expressed by the concentration of reactants with moles raised to their powers and units of rate and rate constant will be the same for that order which does not depend on the concentration of reactants.

Complete Solution :
In this reaction, the rate will be written as :
R= k[A] [B]

Where k is known as the rate constant, if the concentrations of both the reactants were one then, the R=k which means that it won’t depend on the initial concentration of the reactants.
If we take a chemical reaction such as
$aA+bB\to cC+dD$

Then, $R=k{{\left[ A \right]}^{p}}{{\left[ B \right]}^{q}}$
P, q are the orders of an individual reactant and for the whole chemical reaction, it will be the sum of both the orders, n =p + q

- Now, if you want to know what is zero order and first order reaction, then it will depend upon this. If the value of n is 0, it will be zero order reaction and if it is 1 then it first order reaction and so on. Therefore, in the zero-order reaction, the rate is independent of the concentration of reactants and hence, the units of rate and rate constant becomes equal which is mol/L/time.
So, the correct answer is “Option A”.

Note: There is a point which needs to be kept in mind that rate constant depends on the order of the reaction and rate depends on the concentration of the reactants.