In a previous paper,' the authors reported solubility data for the nitrates of sodium, ammonium, barium and silver in anhydrous acetic acid; in none of these cases was a solid solvate obtained, and the saturated solution of the most soluble salt, ammonium nitrate, was found to be o i f l y 0.074 molal a t 3 0 ' .The present paper includes data for the nitrates of lithium and calcium, which were found to be far more soluble than the ammonium salt. In addition, solubility data are presented for the ternary systems silver nitrate-ammonium nitrate-acetic acid and silver nitrate-lithium nitrate-acetic acid.Method Preparation of Materials.-Pure anhydrous acetic acid, and the nitrates of silver and ammonium, were prepared as described in previous papers of this series. Lithium nitrate was recrystallized from a solution which had been acidified with nitric acid, and was dried at 160" to constant weight. A filtered solution of calcium nitrate was evaporated to dryness, and the residue was dehydrated almost completely over a Bunsen flame; it was then heated for twenty-four hours in an oven maintained at 160". Analysis of the product gave Ca, 24.50% (calcd. for Ca(NOa)z, 24.42%).Determination of Solubility.-In the binary systems the synthetic method, as described in previous papers, was used; duplicate determinations were made of equilibrium temperatures, with the usual precautions. The synthetic method was employed also for the system AgNOa-NHI-N03-HC2H302. A number of solutions, each containing acetic acid and one of the other components in a fixed ratio by weight, were used as solvents, and the change in freezing point with varying concentration of the third component was determined. From the data so obtained, solubility isotherms readily could be derived, as in previous work.The system AgNOa-LiNOa-HCnHaOz, however, was studied by the analytical method. An excess of the saturating salt, silver nitrate, was added to solutions containing various fixed ratios of acetic acid and lithium nitrate. These solutions, in tightly stoppered bottles sealed with paraffin, were maintained at 30" in a thermostat, with frequent agitation, for from ten days to two weeks. Filtered samples were then withdrawn, weighed, and analyzed for silver by the X'olhard method.
Analysis of SolidPhases.-In the binary systems, the crystalline phases obtained were analyzed for acetic acid of solvation by direct titration with 0.1 normal sodium hydroxide solution. In the ternary systems, the solids were analyzed for silver 1;y the usual gravimetric method. When ammoniuni nitrate was present. ammonia was de-(1) Davidson and Geer, THIS JOURNAL, 66, 042 (1933). (2) Davidson and Griswold, ibid., 57, 423 (1935).termined by distillation with concentrated aqueous sodium hydroxide solution into standard hydrochloric acid.
ResultsBinary Systems.-In Tables I and 11, S denotes the mole percentage of solute, and T is the corresponding equilibrium temperature. These data are presented graphically in Fig. 1. TABLE I LITHIUM NITRATE-ACETIC ACID
