$37.8\;{\rm{g}}\;{{\rm{N}}_2}{{\rm{O}}_5}$ was taken in a 1 L reaction vessel and allowed to undergo the following reaction at 500 K $2\;{{\rm{N}}_2}{{\rm{O}}_{5(\:{\rm{g}})}}$ $\rightleftharpoons$ $2\;{{\rm{N}}_2}{{\rm{O}}_{4(\:{\rm{g}})}} + {{\rm{O}}_{2(\:{\rm{g}})}}$
The total pressure at equilibrium was found to be 18.65 bar.
Then, ${\rm{Kp}} = $ ________$ \times {10^{-2}}$ [nearest integer]
Assume ${{\rm{N}}_2}{{\rm{O}}_5}$ to behave ideally under these conditions. Given: R = 0.082 bar ${\rm{Lmo}}{{\rm{l}}^{-1}}\;{{\rm{K}}^{-1}}$