The reaction of nitrogen dioxide with carbon monoxide.

${\mathrm{NO}}_2\left(g\right)+\mathrm{CO}\left(g\right)⟶{\mathrm{CO}}_2\left(g\right)+\mathrm{NO}\left(g\right)$

has been studied and the following mechanism has been proposed :

${\mathrm{NO}}_2\left(g\right)+{\mathrm{NO}}_2\left(g\right)⟶{\mathrm{NO}}_3\left(g\right)+\mathrm{NO}\left(g\right)$ (slow)

${\mathrm{NO}}_3\left(g\right)+\mathrm{CO}\left(g\right)⟶{\mathrm{NO}}_2\left(g\right)+{\mathrm{CO}}_2\left(g\right)$ (fast)

What rate law corresponds to this mechanism?

The reaction's slowest step is used to calculate a reaction's pace. Since the first equation in the previous problem is the one that moves most slowly, the rate should be established to create this step. Nitrogen dioxide, 2 moles, is present in the reactant.

As a result,$\text{ Rate }=k{\left[{\mathrm{NO}}_2\right]}^2\mathit{ }$is the formula for the reaction's rate, where k is the rate constant.