sebanyak 60 ml larutan NH3 0.1 M dicampur dengan 50 ml larutan NH4NO3 0.2 M. jika Kb NH3= 1.8x10^5 maka pH campuran yaitu

mol NH3 = 0,1 x 60 = 6mmol
mol NH4OH = 0,2 x 50 = 10mmol

[OH-] = Kb . (6mmol /10mmol)
[OH-] = 1,8 x 10^-5 (6 / 10)
[OH-] = 10,8 x 10^-6
pOH = - log [OH-]
pOH = 6 - log10,8

pH = 14 - (6 - log10,8)
pH = 14 - 6 + log10,8
pH = 8 + log10,8
pH = 8 + 1,03
pH = 9,03