A common laboratory experiment constructed to illustrate the principles of solubility is Qualitative Analysis. This experiment is designed to answer what is present. Unfortunately, there is no spot test for each individual cation, so a scheme was developed, which groups cations based on their solubility characteristics. Each ion is then isolated and identified.
17.7 Applied Qualitative Analysis Scheme
The Group I cations precipitate as chlorides under acidic conditions.
17.7 Group I Separations
17.7 Why does our HCl need to be cold and dilute?
17.7 Group I Analysis
The theory behind the separations of the Group II and Group III encompass all these effects and utilizes the solubility of the sulfide ion in solution.
17.7 Group II and Group III Sulfide Solubility
17.7 Will FeS precipitate?
17.7 At what pH will FeS begin to precipitate?