Determination of hydrogen bonding in water clusters through conductivity (dc) measurements of aqueous solutions of NaCl

摘要

Conductivity (dc) measurements over the temperature range 273le;Tle;360 K of aqueous solutions of NaCl at various concentrations were made and used to establish transport properties of ions in solution. The dynamical properties of the electrolytes were used to establish the nature of the hydrogen bonding in these aqueous systems. Rate equations for ion formation and recombination were used to establish the temperature ranges in which hydrogen bonding dominated in forming polymeric species. Experimental data obtained on the aqueous systems demonstrate that over the range of temperatures 273le;Tle;323 K the water system maintains a structure which appears to be independent of solute concentration. This is evidenced by the nearly constant slope in the Arrhenius plot of the data over that range. For the higher range of temperatures, 323le;Tle;360 K, the slope of the Arrhenius plot varied more than one order of magnitude for the concentration levels studied. An average value of hydrogen bond energy of 2.8 kcalthinsp;molminus;1was obtained from the Arrhenius plots for 273le;Tle;323 K for samples of pure water. This value was taken for pure water as the slopes remained nearly constant in this range of temperatures for all aqueous solutions but varied systematically with ion concentration over the range of temperature 323le;Tle;360 K. If the total range of temperature is chosen, the average value forEHBwas found to be 2.5 kcalthinsp;molminus;1.