Calculate the H+ ion concentration if 0.20M NH3 solution is 2.5% ionized.

Answer 1

0.2 x 0.025 = 0.005

..........NH3 + H2O ==> NH4^+ + OH^-
initial...0.20............0.......0
change....-0.005.......0.005....0.005
equil....0.195.........0.005...0.005

(OH^-) = 0.005.
You know (H^+)(OH^-) = Kw = 1E-14. Substitute and solve for (H^+).