When a mixture of common salt, sulphur, sand, and iron filings is shaken with carbon disulphide, sulphur dissolves because it is soluble in carbon disulphide, while common salt, sand, and iron filings are insoluble in it. After filtration, the filtrate contains dissolved sulphur. Upon evaporating the filtrate to dryness in a china dish, the carbon disulphide evaporates leaving behind sulphur as the residue. Thus, after evaporation, sulphur will be left in the china dish. This is because:
- Common salt (sodium chloride) is not soluble in carbon disulphide.
- Iron filings and sand are also insoluble in carbon disulphide.
- Sulphur is soluble in carbon disulphide and hence is present in the filtrate.
- Evaporation of the solvent (carbon disulphide) leaves sulphur behind.
This conclusion is supported by multiple educational references on the behavior of mixtures with carbon disulphide and solubility characteristics.