The units of rate constant for ${\mathrm{n}}^{\mathrm{th} }$order reaction will be

The general equation for the rate constant expression is,

$\mathrm{K}=\frac{\mathrm{rate} }{{\left(\mathrm{Concentration}\right)}^{\mathrm{n}}}$

$=\frac{\mathrm{mole}.{\mathrm{L}}^{-1}.{\mathrm{time}}^{-1}}{{\left(\mathrm{mol} {\mathrm{L}}^{-1}\right)}^{\mathrm{n}}}$

$=\frac{={\mathrm{mol}}^{1-\mathrm{n}}.{\mathrm{time}}^{-1}}{{\left(\mathrm{mol} {\mathrm{L}}^{-1}\right)}^{\mathrm{n}}}$

$={\mathrm{mol}}^{1-\mathrm{n}}{\mathrm{L}}^{\mathrm{n}-1}{\mathrm{time}}^{-1}$