ELECTROLYTIC DISSOCIATION OF SODIUM SULFATE IN AQUEOUS ETHANOL SOLUTIONS

Abstract

The reducing the degree of electrolytic dissociation of sodium sulphate with the increasing a proportion of ethanol in the hydroalcoholic solution was shown with the conductometric method. It was established that the dissociation constant of sodium sulfate decreases with the increasing a concentration of alcohol in the solution. Physico-chemical properties of sodium sulfate in water-alcohol solutions on salt solubility and dissociation were not studied. In this regard, in the present study we examined an electrolytic dissociation of sodium sulfate in water-ethanol solutions. Firstly, a saturated aqueous solution of sodium sulfate, sodium sulfate solubility process was observed with the aid of crystal optic method. For this purpose, a saturated aqueous sodium sulfate was added, and the calculated amount of alcohol measured on mass of precipitated sodium sulfate decahydrate after drying to constant weight. By weight difference between the original and the precipitate salt (calculated as sodium sulphate) dissolved salt mass was measured. It is generally recognized that the degree of dissociation of the electrolyte in the electrolytic solution depends on the dielectric constant of the solvent. Water (e= 78.53) and ethanol (e = 24.3) has vary large permittivity. Therefore, by varying the alcohol content in the mixture with water it may receive different solvents with a dielectric constant, affecting the equilibrium state in the salt solution. To find the degree of electrolytic dissociation used Na2SO4 conductometric method based on measuring the electrical conductivity of solutions with variable molar concentration of salt and alcohol was applied. The dependence of the molar conductivity of aqueous solutions of sodium sulphate is transformed to direct line in coordinate of Kohlrausch equation. It is known that the degree of electrolytic dissociation of the electrolyte depends not only on its nature, but on the dielectric constant of the medium. Therefore, in water-ethanol solutions sodium sulfate shows the properties of weak electrolyte. In this case, the dependence of conductivity on the molar concentration of sodium sulphate in water-ethanol solutions will have a different appearance.Forcitation:Borisov I.M., Nabiev A.A., Mukhamedyanova A.A., Soliev L., Toshov A.F., Musodzhonova Dzh.M. Electrolytic dissociation of sodium sulfate in aqueous ethanol solutions. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 59-64.