If 20 mL of 0.10 M KOH is added to 40 mL of 0.050 M HCOOH, what is the pH of the mixed solution at 25°C? Ka for HCOOH is 1.8 × 10^–4 at 25°C.
1 Answer
May 18, 2018
Consider the equilibrium,
Moreover, let's assume that the hydroxide ions fully deprotonate one molar equivalent of formic acid.
Let's use a BCA table to organize the calculations,
It fully consumes the formic acid and it leaves us with only formate to equilibrate according to,
where,
According to an ICE table,
and by extension,