\(2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NO}_{2}(\mathrm{g}) ; \mathrm{K}_{2} ...(ii)\)
\(\mathrm{N}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NO}_{2}(\mathrm{g}) ;\)
\(\mathrm{K}=\mathrm{K}_{1} \times \mathrm{K}_{2}\)
therefore, For \(\mathrm{NO}_{2}(\mathrm{g})=\mathrm{N}_{2} / 2(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g})\)