Calculate the pH of a .25 M ammonium acetate (CH3COONH4) soluton. I thought u just did -log(.25) but it keeps saying that i have the wrong answer.

Answer 1

For the salt of a weak base (NH3) and a weak acid (HC2H3O2), the (H^+) = sqrt(KwKa/Kb), then convert (H^+) to pH. Another way, if you want to use logs is
pH = 1/2(pKw + pKa - pKb). The latter is shorter if you know the pK values. I think both pKa and pKb are 4.74. I believe the answer is pH = 7.