For the decomposition of the compound,

For the decomposition of the compound, represented as

$\mathrm{NH}_{2} \mathrm{COONH}_{4}(\mathrm{~s}) \rightleftharpoons 2 \mathrm{NH}_{3}(\mathrm{~g})+\mathrm{CO}_{2}(\mathrm{~g})$

the $\mathrm{K}_{\mathrm{P}}=2.9 \times 10^{-5} \mathrm{~atm}^{3}$.

If the reaction is started with $1 \mathrm{~mol}$ of the compound, the total pressure at equilibrium would be