Abstract

Abstract The D/H ratios of hydrogen gas in equilibrium with aqueous alkali halide solutions were deter-mined at 25 °C, using a hydrophobic platinum catalyst. The hydrogen isotope effect between the solution and pure water changes linearly with the molality of the solution at low concentrations, but deviates from this linearity at higher concentration for all alkali halide solutions. The magnitude of the hydrogen isotope effect is in the order; Kl > Nal > KBr > CsCl ≧ NaBr > KCl > NaCl > LiCl, at concentrations up to a molality of 4 m. The sign and trend of the hydrogen isotope effect is different from that of oxygen. In aqueous alkali halide solutions, the hydrogen isotope effect is influenced by both the cation and the anion species, while the oxygen isotope effect is mainly caused by the cation species. This suggests that the mechanism of hydrogen isotope fractionation between the water molecules in the hydration spheres and the free water molecules differs from the mechanism of the oxygen isotope fractionation. The hydrogen and oxygen isotope effects for alkali halides, except LiCl and NaCl, may be influenced by changes in energy of the hydrogen bonding in free water molecules.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.