An elementary physical chemistry experiment on a three-component system

Abstract

the most frequently studied three-component systems are those consisting of water and two electrolytes having a common ion (1), 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 coordinates, 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

A phase rule experiment: The system lead nitrate-sodium nitrate-water

“…It appears that a laboratory exercise involving the study of the less easily interpreted solid-liquid type of system might be of more value to the student. Two such experiments have been described by O'Brien and co-workers: potassium chloride-hydrochloric acid-water (2) and sodium bromide-hydrobromic acid-water (ft). The method outlined involves analysis by chemical means of fractions of each of the phases present at equilibrium.…”