An ELEMENTARY PHYSICAL CHEMISTRY EXPERIMENT on a THREE-COMPONENT SYSTEM S. JAMES O'BRIEN
AND
CHRISTOPHER L. KENNY
The Creightan University. Omaha, Nebraska
S
INCE the most frequently studied three-component systems are those consisting of water and two electrolytes having a common ion ( I ) , it has seemed desirable to provide an experiment for the introductory physical chemistry course involving a system of this kind. Such an experiment not only illustrates the use of triangular coijrdinates, but also the indirect method employed in determining the composition of the solid phase (2). A study of the system, potassium chloride-
hydrogen chloride-water, has been used and found suitable for this purpose. Since the solutions come to equilibrium quickly, and since they may be analyzed volumetrically, the amount of time consumed in the performance of the experiment is not excessive, a pair of students being able to obtain enough satisfactory data in from six to eight hours in the laboratory. The experimental procedure involves an adaptation of the usual method employed in physical chemistry
