Chemistry - Ionic Equilibrium Question with Solution | TestHub

What is the aqueous ammonia concentration of a solution prepared by dissolving 0.10 mole of ${\mathrm{NH}}_4^{+}{\mathrm{HCOO}}^{-}$ in 1 L of water? ($K_a$ of $\mathrm{HCOOH}=1.8\times 10^{-4}$; $K_b$ of ${\mathrm{NH}}_4\mathrm{OH}=1.8\times 10^{-5}$)