Chemistry - Chemical Kinetics Question with Solution | TestHub

For an elementary reaction, the order of the reaction is equal to the sum of the stoichiometric coefficients of the reactants.

The given elementary reaction is $2{\mathrm{NO}}_{2(\mathrm{g})}⟶2{\mathrm{NO}}_{(\mathrm{g})}+{\mathrm{O}}_{2(\mathrm{g})}$.

The stoichiometric coefficient of the reactant ${\mathrm{NO}}_2$ is $2$.

Therefore, the rate law is given by $\text{Rate}=k[{\mathrm{NO}}_2{]}^2$.

The order of the reaction is $2$.

Answer: 2