CBSE Class 12-science Answered

A change in concentration unit does not change rate constant

                                Let a new unit is m time the first one

The time taken for the completion of the same fraction of change is independent of initial concentration

Put (a-x) = f a, where f = fraction to which the concentration of reaction is reduced from its initial value

Then,                   

Thus tf is independent of a

                    The time taken in reducing the initial concentration to half of its initial value is called half life time (t_0.5)

                                Therefore,

Thus half change time of a first order reaction is independent of the initial concentration of the reactant