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Question
How will you separate a mixture of common salt, sulphur powder and sand ?
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Solution
We will separate a mixture of common salt, sulphur powder and sand by the procedure based on the solubility of these compounds.
Sulphur is soluble in carbon disulphide but insoluble in water. Common salt is soluble in water but insoluble in carbon disulphide. Sand is insoluble in both.
When sand, common salt and sulphur is added to water and stirred vigorously, common salt will dissolve in water but others will not. The solution is then filtered using a filter paper. Filtrate containing common salt is subjected to evaporation to obtain salt.
The residue left on the filter paper contains sand and sulphur. Now, this residue is dissolved in carbon disulphide. Here, sulphur dissolves but sand remains undissolved. This is filtered again to leave behind sand as residue and sulphur solution as filtrate. The filtrate is then subjected to heating to evaporate carbon disulphide and obtain sulphur.
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