Question

State briefly how would you separate and name the process usedto separate:

1-Sulphur from a mixture of carbon particles and powdered roll sulphur.

2-A precipitate of lead sulphate obtained by adding sulphuric acid to a solution of lead nitrate.

3-Nitrogen from liquid nitrogen.

4-Oxygen from a mixture of oxygen and ammonia.

5-Hydrogen from a mixture of hydrogen and carbon monoxide.

Answer 1

1) Seperation of sulphur from carbon particles and powdered roll sulphur can be done by filtration then evaporation.
Process- First dissolve the mixture into carbon disulphide (CS₂). The sulphur will dissolve and carbon will remain as residue. Filter it. Evaporate the filtrate to obtain sulphur.

2) To separate precipitate of lead sulphate obtained by adding sulphuric acid to a solution of lead nitrate we can use the process of filtration or centrifugation.
Pb(NO₃)₂ + H₂SO₄ $\to$ PbSO₄(s) + 2HNO₃(aq)
Process- Filtration: Simply filter the solution using filter paper. The solid lead sulphate will obtain on filter paper.
Centrifugation- Centrifuge the solution, the solid lead sulphate will settle down. Then decant the above liquid to obtain the precipitate.

3) Nitrogen can be obtained from liquid nitrogen by increasing the temperature of liquid nitrogen. Nitrogen remain liquid at -190^oC, so above this temperature liquid will go back to gas.

4) To separate oxygen from mixture of oxygen and ammonia, we can compress and cool the mixture. The ammonia will liquify and hence oxygen can be separated.

5) Hydrogen can be separated from mixture of hydrogen and carbon monoxide by liquefaction, i.e. same as above compressinf and cooling one of the gas to obtain the other.