For the reaction $2{\mathrm{NO}}_2( \mathrm{g})\rightleftharpoons 2\mathrm{NO}\left(\mathrm{g}\right)+{\mathrm{O}}_2( \mathrm{g})$, when $K_p$ and $K_c$ are compared at 184 °C, it is found that (Given that $R=0.00831 \mathrm{kJ}{ \mathrm{mol}}^{-1}{ \mathrm{K}}^{-1}$.)

The expression relating $K_p$ and $K_c$ is $K_p=K_c(RT{)}^{\Delta v_g}$ where  $\Delta v_{\mathrm{g}}$ is the change in the stoichiometric numbers of gaseous species in the chemical equation when reactants are converted into products. For the given reaction, $\Delta v_{\mathrm{g}}=+1$ Hence

$(RT{)}^{\Delta v_{\mathrm{g}}}=\left(8.314 \mathrm{J}{ \mathrm{K}}^{-1}{ \mathrm{mol}}^{-1}\right) (457 \mathrm{K})=3799.5 \mathrm{J}{ \mathrm{mol}}^{-1}$

Since $K_p=K_c\left(3799.5 \mathrm{J}{ \mathrm{mol}}^{-1}\right)$ it follows that $K_p>K_C$