a) 0.001 moles of ammonia (NH3) are added to 1 liter of pure water. Determine the final pH, [NH4 +], and [NH3] in the solution. The pKa of NH4+ is 9.25. Hint: to solve, you will need to use a charge balance expression, equilibrium, and mass balance expressions. You can also assume that the concentration of [H+] is negligible compared to other species in solution.

(b) How does the pH, [NH4 +], and [NH3] change when 0.001 moles of HCl, a strong acid, are added to the solution described in part (a)? HCl is added from a concentrated stock solution, so the volume change is negligible.

(c) Determine the concentration of [NH3] and [NH4 +] in a pH 7.0 solution in equilibrium with an atmosphere with partial pressure of NH3(g) of 10-7 atm. The Henrys constant (KH) for NH3 is 101.8 mol L-1 atm-1 .