Chemistry - Chemical Equilibrium Question with Solution | TestHub

For the equilibrium$\mathrm{L}\mathrm{i}\mathrm{C}\mathrm{l}.3\mathrm{N}{\mathrm{H}}_3\left(\mathrm{s}\right)\rightleftharpoons \mathrm{L}\mathrm{i}\mathrm{C}\mathrm{l}.\mathrm{N}{\mathrm{H}}_3\left(\mathrm{s}\right)+2\mathrm{N}{\mathrm{H}}_3\left(\mathrm{g}\right);$${\mathrm{K}}_{\mathrm{P}}=9\mathrm{a}\mathrm{t}{\mathrm{m}}^2$at$37°\mathrm{C}$. A 5 L vessel contains 0.1 mole of$\mathrm{L}\mathrm{i}\mathrm{C}\mathrm{l}.\mathrm{N}{\mathrm{H}}_3$. How many mole of$\mathrm{N}{\mathrm{H}}_3$should be added to the flask at this temperature derive the backward reaction for completion? (use R = 0.082 atm-L/mol K)