Question

What mass of NH4Cl must be added to 0.750 L of a 0.100 M solution of NH3 to give a buffer solution with a pH of 9.26? Kb(NH3) = 1.8 x 10^-5. (Hint: Assume a negligible change in volume as the solid is added.)

Answer 1

pH = pKa + log [(base)/(acid)]
Calculate pKa = pKw/pKb
(base) = NH3
(acid) = NH4Cl
Post your work if you get stuck.

Answer 2

25.5