The decomposition of ${\mathrm{N}}_2\mathrm{O}$  into ${\mathrm{N}}_2$ and ${\mathrm{O}}_2$  in presence of gaseous argon follows second order kinetics with $k=\left(5.0\times {10}^{11}\mathrm{L}{\mathrm{mol}}^{-1}{\mathrm{s}}^{-1}\right)e$ The energy of activation of  the reaction is :