Answer
See the answer below
Work Step by Step
The general expression for the unit of rate constant of a particular reaction is given by
$$unit = (mol/L)^{1-n} \times s^{-1}$$
where $n$ is the order of the reaction
Therefore,
For the Zero order reaction, $n = 0 $
$$unit_0 = (mol/L)^{1-0} \times s^{-1} = mol L^{-1} s^{-1}$$
For the first order reaction, $n=1$
$$unit_1 = (mol/L)^{1-1} \times s^{-1} = s^{-1}$$
For the second order reaction, $n=2$
$$unit_2 = (mol/L)^{1-2} \times s^{-1} = mol^{-1} L s^{-1}$$