Precipitation and dissolution potentials of electrolytes in D2O, acetone, and formamide

Precipitation, dissolution, diffusion, and phase potentials of,, and have been measured in, acetone, and formamide in nitrogen atmosphere. The techniques adopted were similar to those used previously by Rastogi and Shukla for,,, and in. The true dissolution and precipitation potentials were found to be negative for and in and (smaller numerically in the latter) and for in. However, the dissolution potential of and in acetone and formamide and of in acetone is positive and of higher magnitude. The temperature, concentration, and time dependence of the dissolution potentials have been investigated. The decay of the precipitation potential and of the apparent diffusion potential with time has been studied. The experimental results show that the precipitation potential increases with undercooling. The transport number of K+ and Br− in formamide has also been measured. The results support the hypothesis that the precipitation and dissolution potentials arise on account of the unequal mobilities of the ions moving to and away from the crystal face.