The $K_p$ for following reaction is $2.25\times {10}^{-2}{\mathrm{atm}}^2$
${\mathrm{NH}}_4\mathrm{CN}\left(\mathrm{g}\right)\rightleftharpoons {\mathrm{NH}}_3\left(\mathrm{g}\right)+\mathrm{HCN}\left(g\right)$
The value of equilibrium pressure (in atm) above ${\mathrm{NH}}_4\mathrm{CN}\left(\mathrm{s}\right)$ is :