separation of salts

Heat the mixture.

Ammoniumchloride undergoes sublimation and it can be collected by solidifying the vapouron a cool surface. Sodium chlorideremains unchanged on heating, and thus the residue is sodium chloride.

To Leo :

It is impossible to separate two soluble salts by crystallization, especially when their solubilities are close, because most of the solute remains in the solution and would NOT be crystallized out.

2013-12-14 03:30:19 補充：
Besides, it is WRONG deduction that sodium chloride, a salt with a "flat" solubility curve, will be firstly crystallized.

To Leo :

Both sodium chloride and ammonium chloride are very soluble in water.

gradually add water to the mixture, sodium chloride is very soluble while the solid remained is ammonium chloride.

2013-12-13 00:00:27 補充：
They can also be separated by dissolving in boiling water and filtered. When the hot filtrate is cooled down slowly, according to their solubility curve, sodium chloride will crystallize out first, which can be removed by filtration.

2013-12-13 00:00:54 補充：
http://hrsbstaff.ednet.ns.ca/dawsonrj/12%20Chem/Lab%20Activities/Solubility%20Curve%20HWHS_files/image003.jpg