Solubility of NaI in water, methanol, ethanol, propan-2-ol, and also in water + methanol, water + ethanol, and water + propan-2-ol binary mixtures have been experimentally measured using a gravimetric method at temperatures (298.15.303.15, 308.15, and 313.15) K. The combined NIBS (nearly ideal binary solvent)–Redlic–Kister equation is used to fit experimental solubility data at constant temperature. The densities of the saturated solutions are also reported in pure and binary solvent mixtures at temperatures mentioned above. Thermodynamic functions including ΔH soln 0, ΔG soln 0, and ΔS soln 0 of solution of NaI are obtained from the modified van’t Hoff equation. A comparison of the relative contributions by enthalpy (ζH) and entropy (ζTS) is made which indicated that the main contributor to the positive standard molar Gibbs energy of solution of NaI is the entropy for solution of NaI in water + methanol having x C 0 < 0.5 and for all other solutions it is enthalpy.

The solubility of potassium iodide in ethanol + water binary solvent was measured over the entire composition range from 0 to 1 weight fraction of ethanol at (298.15, 303.15, 308.15, and 313.15) K. The densities of the saturated solutions are also reported. Equations are given for the solubility and density of the saturated solutions as functions of mole fraction of ethanol and temperature.

The solubility of potassium iodide in a propan-1-ol + water binary solvent mixture was measured over the entire composition range from (0 to 1) mass fraction of propan-1-ol at (298.15, 303.15, 308.15, and 313.15) K. The densities of the saturated solutions are also reported. The equation given for the solubility of the saturated solutions is correlated with the mole fraction of propan-1-ol and the temperature and density of the solution.

Density of water, methanol, ethanol and water+methanol, water+ethanol binary solvent in pure form were experimentally measured. In these same series of solvents 2-naphthol was added to make saturated solutions of 2-naphthol at equilibrium. These saturated supernatant solutions were collected to measured densities and molalities of 2-naphthol at (293.15 to 313.15) K for comparative studies and experimental data used to calculate the excess molar volumes (V E ), apparent molar volume (V Φ ). Redlich−Kister Equation was used to calculate excess molar volumes (V E ) to correlate with the experimental excess molar volumes (V E ) of binary solvent mixture. Regressed Parameters Ai obtained from Redlich−Kister Equation were used for calculation of partial excess molar volumes at infinite dilution (V̅ i E,∞). Molecular interaction was explain by using Gaussian 09W software, DFT/B3LYP 6-31(G)d as basic set.-73 -investigate. We have undertaken the measurements of densities of pure solvents, binary solvent mixtures and saturated solutions of 2-naphthol in water + methanol and water + ethanol binary solvents over the entire composition range from 0 to 1 mole fraction of methanol, ethanol. Apparatus and Procedure:-The apparatus and procedures used for density measurement have been described earlier in detail [13,14]. Briefly in this work; an excess amount of 2-naphthol was added to the binary solvents mixtures prepared by weight (Shimadzu, Auxzzo) with an uncertainty of ± 0.1 mg, in a specially designed 100 ml jacketed flask. Water was circulated at constant temperature between the outer and inner walls of the flask. The temperature of the circulating water was controlled by thermostat to within (± 0.1) K. The solution was continuously stirred using a magnetic stirrer for sufficient time (about 3hr) so that equilibrium is assured, no further solute dissolved, and the temperature of solution is same as that of circulating water; the stirrer was switched off and the solution was allowed to stand for 1hr. Then 5 ml of the supernatant liquid was withdrawn from the flask in a weighing bottle with the help of pipette which is hotter than the solution. Solutions were dried gravimetrically till constant weight of weighing bottle was reached. Molality of 2-naphthol was calculated by constant weights of solute. This flask solution was used to fill bicapillary pycnometer.Densities were determined using a 15 cm 3 bicapillary pycnometer as described earlier [15,16]. For calibration of pycnometer triply distilled and degassed water with a density of 0.99705 g·cm −3 at 298.15 K was used. The filled pycnometer (without air bubble) with experimental liquids was kept in a transparent walled thermostat maintained at constant temperature (± 0.1 K) for 10 to 15 min. to attain thermal equilibrium. The heights of the liquid levels in the two arms were measured with the help of a travelling microscope, which could read to 0.01 mm. The estimated standard uncertainty of the density measurements of the solvent and binary mixtures was 10 kg·m −3 . Resul...

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