Lesson 2: Cation Analysis: Group Separation
This lesson focuses on the systematic separation of cations into different groups based on the solubility of their chlorides, sulfides, or carbonates. This process uses a specific group reagent for each group.
- Group 1 Cations: These cations (, , ) precipitate as chlorides with the group reagent, dilute . The lesson covers the confirmatory tests for each of these cations, for example, the formation of a dark complex with ammonia for silver.
- Group 2 Cations: After removing Group 1 cations, the group reagent for Group 2 is gas in the presence of dilute . This precipitates cations like , , and as sulfides. Students will learn the different colored precipitates and the confirmatory tests.
- Group 3 Cations: The group reagent for Group 3 is ammonium hydroxide () in the presence of ammonium chloride (). Cations like , , and precipitate as hydroxides. The lesson details the colors of these precipitates and their confirmatory tests. For example, forms a white gelatinous precipitate
