Interdiffusion in Dilute Solutions of Silver Nitrate in Alkali Nitrates

Abstract

The ordinary diffusion coefficients in dilute solutions of AgNO8 molten in LiNO8, NaNO8, KNO8, RbNO8, and CsNO8 have been measured with a porous frit technique. The results can be summarized in Arrhenius equations: Solvent: LiNO3 DV 12 = 7.00 × 10-3 exp{-7270/RT} (272-399°C) NaNO3 DV 12 = 2.23 × 10-3 exp{5430/RT} (310-382°C) KNO3 DV 12 = 0.354 × 10-3 exp{-3530/RT} (337-386°C) RbNOO3 DV 12 = 4.00 × 10-3 exp{-6670/RT} (317-384°C) CsNOO3 DV 12 = 2.88 × 10-5 (428°C) where DV 12 is expressed in cm2 s-1, R in cal mole-1 degree-1, and T in degrees Kelvin. The results are in good agreement with chronopotentiometric data on the AgNO3—NaNO3 and AgNO3—CsNO3 systems 1 and also with some recent data on the AgNO3—NaNO3, AgNO3—KNO3, and AgNO3 — RbNO3 systems obtained with an optical method 2. Interionic friction coefficients are calculated. Only three ionic species are present in the AgNO3—LiNO3, AgNO3—NaNO3, and AgNO3—KNO3 mixtures while there is evidence of “complex ions” in AgNO3—RbNO3 and AgNO3—CsNO3.