Activity coefficients in the system H2O–NaCl–MgSO4 at 25°C

The system H2O–NaCl–MgSO4 was studied by both the isopiestic and the electromotive force (e.m.f.) methods, and mean activity coefficients of NaCl and MgSO4 were measured at 25 °C at ionic strengths up to 0.72. Difficulty was encountered in extrapolating the isopiestic results to infinite dilution and an extrapolation was chosen which made the isopiestic results consistent with e.m.f. results on the same system. Harned's rule was not obeyed for either salt.