Question

How can we separate the mixture of salt,sand and sulphur .

Answer 1

The mixture contains sulphur, common salt(sodium chloride) and sand. They can be separated as follows:

Add water to the mixture. Salt will dissolve in water.
Filter the solution.
Filterate is solution of Salt and residue contains sulphur and sand.
Evaporate the filterate, water will vapourize leaving behind salt.

To the residue containing sulphur and sand add carbon disulphide, this will dissolve sulphur.

Filter this solution.

The filterate will contain sulphur dissolved in carbon disulphide and residue will be sand.
Evaporate the filterate, to obtain crystals of Sulphur.