STANDARD POTENTIAL OF THE AGCL/AG ELECTRODE AND THE 2ND DISSOCIATION-CONSTANT OF PHOSPHORIC-ACID IN 20, 50, AND 80 MASS PERCENT 2-METHOXYETHANOL + WATER FROM -10-DEGREES-C TO +37-DEGREES-C

Solvents consisting of 2-methoxyethanol (20, 50, and 80 mass % + water were chosen in a continuing study designed to shed light on the behavior of electrolytes in mixed media at temperatures extending below 0-degrees-C. Electromotive-force measurements of cells with hydrogen and AgCl/Ag electrodes in the range from - 10 to + 37-degrees-C, together with a recalculation of earlier data in the literature, yielded values of the standard potential of the HCl in the mixed solvents. A disagreement of literature values for the standard potential in the 80 mass % solvent was resolved. A further series of measurements of phosphate buffer solutions in 20 and 50 mass % 2-methoxyethanol + water led to values for the dissociation constant (pK2) and associated thermodynamic function for dissociation of the primary phosphate ion H2PO4- in these mixed solvents.