Electrical conductances of sodium bromide and sodium tetraphenylborate in 2-ethoxyethanol + water mixtures at 308.15, 313.15, 318.15 and 323.15 K

Abstract

The electrical conductances of the solutions of sodium bromide (NaBr) and sodium tetraphenylborate (NaBPh 4) in 2-ethoxyethanol + water mixed solvent media containing 0.25, 0.50 and 0.75 mass fractions of 2-ethoxyethanol ( w 1) have been reported at 308.15, 313.15, 318.15, and 323.15 K. The conductance data have been analyzed by the 1978 Fuoss conductance–concentration equation in terms of the limiting molar conductance ( Λ 0), the association constant ( K A) and the association diameter ( R). Of the two electrolytes investigated here, sodium bromide exists essentially in the form of free ions in aqueous 2-ethoxyethanol solutions over the entire temperature range investigated. However, slight ionic association was observed for sodium tetraphenylborate—the extent of which increases with increasing amount of 2-ethoxyethanol in the present mixed solvent media. The solvations of the bromide ion and of the sodium ion were found to be gradually weakened as the 2-ethoxyethanol content of the medium increases. Furthermore, the limiting molar conductivity values of the two electrolytes increase as the temperature increases in all 2-ethoxyethanol + water mixtures which have been described by polynomial equations.