Thermodynamic quantities of surface formation of aqueous electrolyte solutions - II. Mixed aqueous solutions of NaCl and MgCl2

The surface tensions of binary salt mixtures made up from NaCl and MgCl2 in aqueous solution were measured as a function of concentration and temperat ure. By analyzing the results, the thermodynamic quantities of surface form ation such as entropy (Delta s), Helmholtz free energy (Delta f), and energ y of surface formation (Delta u) were evaluated. The Delta f of the mixture s positively deviates from the straight line connecting those of NaCl and M gCl2 aqueous solutions. On the other hand, Delta s shows negative deviation from the linear relation. (C) 1999 Academic Press.