Apparent molar volumes of electrolytes. Part 3.—Some 1-1 and 2-1 electrolytes in aqueous solution at 0, 5, 15, 35, 45, 55 and 65 °C

Abstract

The apparent molar volumes of NaCl, KCl, KBr, KI, BaCl2 and CaCl2 have been determined in the concentration range 0.001-.0 M and at 0.05, 5.0, 15.0, 35.0, 45.0, 55.0 and 65.0 °C. A magnetically-operated dilatometer has been used for the very dilute solutions. The theoretical Debye-Hückel apparent molar volume limiting slope at each temperature is satisfactorily approached in very dilute solutions by the electrolytes studied. In the temperature range 0–65 °C, there is a marked decrease in the concentration dependence of the apparent molar volume of each electrolyte as the temperature increases. For each electrolyte, there is a rapid increase in the limiting apparent molar volume as the temperature increases until a maximum value is reached in the temperature range 35–60 °C. This maximum occurs at about 60 °C for NaCl, KCl, KBr and KI, at about 45 °C for BaCl2 and at about 35 °C for CaCl2.