Partial molar volumes and heat capacities of single ions in aqueous solution over the temperature range 288.15 to 328.15 K

Abstract

The partial molar volumes, V⁰₂, and partial molar heat capacities,C⁰_p,2, at infinite dilution have been determined for the electrolytes tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, sodium tetraphenylborate and sodium bromide in aqueous solution over the temperature range 288.15 to 328.15 K. These results, along with literature data for sodium chloride, were used to derive V⁰₂ and C⁰_p,2 values for the electrolyte tetraphenylphosphonium tetraphenylborate (Ph₄PBPh₄). An extrathermodynamic assumption based on Ph₄PBPh₄ as the reference electrolyte was used to evaluate the contributions of the cation and anion and thence to establish scales of single-ion volumes and heat capacities. Using the proton as an example, comparisons were made with other single ion scales reported in the literature.