What is the pH of the solution formed by mixing 25mL of a .15M solution of NH3 with 25mL of .12M HCl? (Kb of NH3 = 1.8e-5)
Because this is a strong acid and a weak base, we need to calculate the moles of each one separately..
.12M of HCl x .025L = 3e-3 moles of H+ in solution.
.15M of NH3 ---> [NH4][OH]/[NH3] = Kb ---> .15 x 1.8e-5 = [NH4][OH]
[OH] = 1.643167673e-3, however this is molar conc. so multiply it by .025L = 4.107919e-5
There are a lot more moles of acid than base, so why does the given answer have a basic pH?
Am I doing the setup or calculation incorrectly? thanks