In this paper we describe a new qualitative analysis laboratory experiment involving cations and anions commonly found in natural water samples. Simple separation techniques are used followed by precipitation or color-complex formation as confirmation tools. Our students perform this as a limited discovery experiment, working through the procedures with a mixture of all species to determine the appearance of a positive result, then conducting the tests with an instructor-prepared unknown and a natural water sample. In our course, the anion portion was also used as an assessment tool. Acid–base chemistry, solubility, complex formation, and oxidation–reduction are all illustrated in this experiment.
Crawford et al. (Fri,) studied this question.