Flow Adaptation of the Isotopic Dilution Method for the Study of Ionic Hydration

Abstract

A method is described for rapid mixing and sampling in the application of the isotopic dilution technique to the study of ionic hydration. The behavior of solutions of various salts has been compared with that of solutions containing a hydrated cation of known formula, namely Cr(H2O)6+ + +. The holdback of water per ion of Al+ + + is the same (within 0.4 molecules of H2O as that of Cr+ + +, and t½ for the exchange of Al(H2O)6+ + + with H2O is >0.02 sec. at 25°·t½ for the exchange of water between Ni+ + (aq) or Fe+ + + (aq) and solvent is less than 0.02 sec.