In this problem we derive Equation $29.45$, the rate law for the oxidation reaction $2 \mathrm{CO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{~g}) \longrightarrow 2 \mathrm{CO}_{2}(\mathrm{~g})$ assuming that the reaction occurs by the Langmuir-Hinshelwood mechanism. The overall rate law for this mechanism is
$$
v=k_{3} \theta_{\mathrm{Co}} \theta_{\mathrm{o}_{2}}
$$