Closed System Electrical Conductance Apparatus for Non-Aqueous Systems

Studies of electrical conductance in non-aqueous solvents is often hampered by the ability of the solvents to absorb moisture and/or carbon dioxide from the atmosphere. Even small traces of these impurities may alter considerably the conducting properties of the solution and render the measurements invalid. The errors become especially important when the solutes are highly hygroscopic themselves. The usual technique for cases where contact of solutions with the atmosphere is to be avoided is to prepare them in a conventional dry-box. This renders the operation tedious and time-consuming especially when a number of exact dilutions have to be made. These disadvantages could be eliminated by the use of a closed system in which the solvent is purified, the solution prepared, accurate dilutions made, and the electrical conductance measured in a completely inert atmosphere. A closed system has been recently described (1) in which it is possible to prepare the solutions and to measure their conductances out of contact with atmospheric moisture. This apparatus is only applicable when the solute is in a liquid state and it is not convenient for carrying out precise successive dilutions. A modification which seems to eliminate the difficulties of this apparatus has been constructed, and its performance has been found to be quite satisfactory in a study of the electrical conductance of interhalogen compounds in non-aqueous solvents (2).