Freezing potentials in heavy water

Abstract

Abstract The freezing of a dilute aqueous solution is accompanied by a charge separation (Workman-Reynold's “freezing potential”) between the advancing ice front (negatively charged) and the unfrozen solution (positively charged). Potentials of 10 and 25 V are observed when freezing 10 −3 and 10 −4 M KCl solutions at a rate of 20 μ/sec. The potential is generated within seconds after freezing has begun, reaches a maximum value, and decays slowly as freezing progresses. Gentle stirring obliterates the potential. The freezing of 10 −3 and 10 −4 M KCl solutions in heavy water (D 2 O) has now been studied. The observed behavior is similar to that observed in H 2 O. Freezing potentials occur in the solidification of dilute solutions of electrolytes in D 2 O as with ordinary water. The magnitude of the freezing potentials observed with heavy water is similar to that observed with ordinary water (H 2 O), both with respect to magnitude and concentration dependence. Notable differences are observed only for very low concentrations where a reversal of sign of the potential is observed.