Acidity constant of formic acid
Abstract
The acidity constant of formic acid has been re-determined by precise e.m.f. measurements on cells without liquid junctions containing formic acid-sodium formate buffer solutions. The pKa is 3.739±0.001 at 25°C. This result agrees exactly with Saxton and Darken's value obtained by conductivity measurements but not with Harned and Embree's value obtained from e.m.f. measurements.