What is meant by the 'rate constant, k' of a reaction ? If the concentration be expressed in mol `L^(-1)` units and time in seconds, what would be the units for k (i) for a zero order reaction and (ii) for a first order reaction?

Explanation

Rate constant k : The rate constant k is equal to the rate of reaction when the concentration of the reactant in unity.
It depends upon the order of reaction as well as temperature:
Unity for k :
(i) for a zero order reaction : mol `L^(-1)s^(-1)`
(ii) for a first order reaction : `s^(-1)`.