Write the half-life $({t_{1/2}})$ equation and its unit for the following reactions:
$(i)$ Zero order reaction
$(ii)$ First order reaction

(N/A) $(i)$ For a zero order reaction,the half-life equation is $t_{1/2} = \frac{[R]_0}{2k}$. The unit of the rate constant $k$ is $\text{mol L}^{-1} \text{s}^{-1}$,so the unit of $t_{1/2}$ is $\text{s}$ (time).
$(ii)$ For a first order reaction,the half-life equation is $t_{1/2} = \frac{0.693}{k}$. The unit of the rate constant $k$ is $\text{s}^{-1}$,so the unit of $t_{1/2}$ is $\text{s}$ (time).