Determination of Ion Activity Coefficients in Aqueous Solutions of Mixed Electrolyte with a Common Ion: NaNO3 + NH4NO3, NH4Cl + LiCl and KBr + KCl

Ion-selective electrodes have been used to measure the activity coefficients at 298.15 K of individual ions in aqueous solutions of mixed 1:1 electrolytes with a common ion for the systems NaNO3 + NH4NO3, NH4Cl + LiCl and KBr + KCl. These values were obtained from electrode potential measurements of the common ion against an Ag-AgCl single-junction reference electrode filled with 4 mol · kg-1 KCl solution saturated with AgCl. The Henderson equation was used to estimate the value of the liquid-junction potential.