Studies on the Equilibria of α‐Phthalic and Phosphoric Acids in Mixed Methanol — Water Mixture (50% w/w)

The secondary dissociation constants of α‐phthalic and phosphoric acids have been determined in 50% w/w methanol‐water mixture from the e.m.f measurements of the cell of the type: Pt; H 2 (1 atm), M 2 A(m), MHA(m), MCl, AgCl; Ag at different temperatures (288.15–308.15 K) and at different ionic strengths. The thermodynamic values ΔG°, ΔH°, ΔS° for the respective equilibria are estimated. The possibility of using these acids as basis for some buffer solutions in 50% methanol – water mixture is discussed.