Data on primary hydration characteristics of aqueous electrolytes

Abstract

The data presented in this article support the research article entitled "Development of a rationale for decoupling osmotic coefficient of electrolytes into electrostatic and nonelectrostatic contributions" (Sahu and Juvekar, 2018) [1]. In this article, we have presented the plots of osmotic coefficients against molality for more than hundred aqueous single electrolytes at 25 °C. The linear regions in these plots are marked to show that they are present in all these electrolytes and that these regions extend over a wide range of concentrations. Slopes of the linear regions are used to estimate the primary molar hydration volume as well as the primary hydration number of these electrolytes. These values are also listed and the method of estimation is presented with sample calculation. These data, not only reinforce the observations made in the main article but also provide useful measures for estimation of the nonelectrostatic contribution to the osmotic coefficient.

Development of a Model for Electrostatic Contribution to the Osmotic Coefficient of Aqueous Electrolytes

“…In this work, we have proposed a model for predicting the contribution from electrostatic interaction to the osmotic coefficient, which is consistent with our previous work . In the previous work, we have abbreviated the electrostatic interaction to the osmotic coefficient as, φ e E and the nonelectrostatic interaction to the osmotic coefficient as, φ e NE .…”

“…After comparison with D-H theory, we have shown that our model is more accurate than the standard D-H theory for NaCl, LiCl, KCl, MgSO 4 , and MgCl 2 solutions. The continuation of this work (correlating the values of a and R * with hydration radius which are estimated in our previous work, correlating the values of ε* with the Booth model, and analysis of temperature dependence of model’s parameters) is under process, and should help us in the future to better understand electrostatic and nonelectrostatic interactions in aqueous electrolyte solutions.…”

“…The quantity h , represents the primary hydration number of the electrolyte, that is, the number of water molecules tightly bound to the electrolyte. However, v h can be calculated by using slope analysis . Since the molar hydrated ion volume, v h is known, eq can be used to estimate φ e NE , the nonelectrostatic contribution in the entire concentration range (up to the solubility limit).…”

“…In our method, we include both electrostatic and nonelectrostatic contributions to estimate the osmotic coefficient for the dilute solution and hence the total excess osmotic coefficient is given by the following equation where a is estimated using the procedure described in section-4.1 and second term of eq is the nonelectrostatic contribution obtained in the our previous work …”

“…This paper is related to our previous paper, in which a rationale was provided to segregate the electrostatic contribution from nonelectrostatic contribution to the osmotic coefficient for more than hundred electrolytes. The nonelectrostatic contribution to the osmotic coefficient was related to the primary hydration number of the electrolyte.…”