You need two equations to solve simultaneously. Equation 1 is the Henderson-Hasselbalch equation.
pH = pKa + log (base)/(acid)
5 = pKa + log (base/acid)
Substitute and solve for ratio (base)/(acid).
Equation 2 is
(acid) + (base) = 0.2 M
Solve the two equations for (base) and (acid) and you have your answers. acetic acid is the acid and sodium acetate is the base.
Calculate the formal concentrations of acetic acid and sodium acetate necessary to prepare a buffer solution of pH 5 that is 0.20M in total acetate?
1 answer
2 answers