Question

How will you separate a mixture containing carbon, sulphur and sodium chloride?

Answer 1

Separation of a mixture containing Carbon $\left(\mathrm{C}\right)$, Sulphur $\left(\mathrm{S}\right)$ and Sodium chloride $\left(\mathrm{NaCl}\right)$:

Step-1: Separation of sodium chloride from the mixture

• Water is added to the mixture.
• On addition of water, sodium chloride gets dissolved in water whereas carbon and sulphur remain undissolved.
• On filtering it, the undissolved carbon and sulphur is obtained as a residue and the filtrate is obtained.
• Filtrate containing sodium chloride is subjected to evaporation.
• On evaporation, water is evaporated and solid sodium chloride is left behind and separated from the mixture.

Step-2: Separation of sulphur from the residue

• Carbon disulphide $\left({\mathrm{CS}}_2\right)$ is added to the residue obtained in step-1.
• Sulphur present in the residue dissolves whereas carbon remains insoluble in it.
• On filtering it, insoluble carbon is obtained as a residue and is separated from the mixture.
• This is because carbon is neither soluble in water nor carbon disulphide.

Step-3: Separation of sodium chloride

• The filtrate containing sodium chloride is subjected to evaporation.
• Once the water present in the filtrate evaporates, the solid sodium chloride remains behind as a white powder.

Thus, the components of the mixture get separated based on their solubility in different solvents.