Ionization constants and related thermodynamic quantities of (CH₂)_n(CO₂H)₂ (n = 0, 1, 2, 3 or 4) from e.m.f. measurements in HCONH₂

Abstract

The first and second ionization constants of the dicarboxylic oxalic, malonic, succinic, glutaric and adipic acids in formamide have been determined at nine temperatures ranging from 5 to 45°, using cells of type:                      Pt, H₂|H₂A(m₁), KHA(m₂), KCl(m₃)|AgCl-Agand                     Pt, H₂|KHA(m₁), K₂A(m₂), KCl(m₃)|AgCl-Ag respectively, where H₂A stands for dicarboxylic acids, KHA for mono- potassium salts and K₂A for potassium salts of dicarboxylic acids. These values have been utilized to evaluate the standard thermodynamic quantities ΔG°, ΔH° and ΔS° associated with the first and second ionization processes at 25°.