Apparent Molal Volumes of Aqueous Sodium Tetraphenylboron Solutions from 0° to 60° C

Precision density measurements were made on dilute aqueous solutions of sodium tetraphenylboron as a function of concentration (0.001 to 0.1m) and temperature (0° to 60° C). The apparent and partial molal volumes for these solutions were calculated from these density data. The Debye-Hückel theoretical limiting law slope for φv as a function of the square root of molar concentration is approached at all the temperatures studied. The deviations from the limiting law are negative at all the temperatures studied and become less negative as the temperature is increased. The effect of temperature on the partial molal volumes of sodium tetraphenylboron at infinite dilution is similar to other common electrolytes—i.e., appears to go through a maximum or is negative. The ion-ion and ion-water interactions responsible for the observed behavior of the φv's as a function of temperature and concentration are briefly discussed.