Studies of concentrated electrolyte solutions using the electrodynamic balance. 1. Water activities for single-electrolyte solutions

摘要: An electrodynamic balance has been used to measure the water activity as a function of solute concentration at 20 °C for three aqueous electrolyte mixtures: NaCI-KCI, NaCl-KBr, and NaCl-(NH_4)_2SO_4. The measurements were performed by levitating single, charged particles these mixtures within measuring mass surrounding relative humidity. deliquescence behavior mixed-electrolyte was also observed. For alkali halide mixtures, low-concentration data consistent with earlier investigations. Data obtained higher concentrations than previously reported. amount in NaC1-(NH_4)_2SO_4 after drying unknown. This, together lack reported this mixture, complicated analysis experiments. Three models solutions-the Zdanovskii-Stokes-Robinson, Reilly-Wood-Robinson, Pitzer methods-agreed well experimental NaCl-KCl NaCl-KBr systems over range that could be applied. mixing rules' predictions observations NaCl-(NH_4)_2SO_4 system assuming small retained drying.