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�.