The observations described involve different compounds of chromium with the general formula CrCl6H2O.
1. **Violet Compound**:
- This compound is violet in color.
- When dissolved in water, it forms a solution from which all the chlorine can be precipitated as AgCl when aqueous silver nitrate is added.
- The formation of a white precipitate of silver chloride (AgCl) indicates the presence of chloride ions (Cl-) in the solution.
- The complete precipitation of chlorine as AgCl suggests that all chloride ions are in the form of chloride ions in this compound.
2. **Green Compound**:
- This compound is green in color.
- It produces an aqueous solution from which only one third of the chlorine can be precipitated with aqueous silver nitrate.
- The formation of a white precipitate of silver chloride (AgCl) upon the addition of silver nitrate indicates the presence of chloride ions (Cl-) in the solution.
- The fact that only one third of the chlorine can be precipitated suggests that only one third of the chloride ions are present as chloride ions in this compound.
In summary, the differences in the behavior of these compounds towards silver nitrate indicate variations in the oxidation state or coordination environment of chromium, leading to different proportions of chloride ions being available for precipitation as silver chloride.
