We seperate sand by filtration and iron fillings by magnets and ammonium chloride by sublimation and sodium chloride by evaporation.

Separation of Mixture: Sand, Iron Fillings, Ammonium Chloride, and Sodium Chloride

Introduction:
When faced with a mixture of different substances, it is often necessary to separate them in order to obtain individual components. In this case, we have a mixture consisting of sand, iron fillings, ammonium chloride, and sodium chloride. Each of these substances has distinct properties that can be utilized for separation.

Separation Techniques:

1. Magnetic Separation: Iron fillings can be easily separated from the mixture using a magnet. This technique takes advantage of the magnetic properties of iron. The iron fillings will be attracted to the magnet, allowing them to be separated from the rest of the mixture.

2. Sublimation: Ammonium chloride, being a volatile substance, can be separated from the mixture through sublimation. When heated, ammonium chloride undergoes sublimation, converting directly from a solid to a gas without passing through the liquid phase. By heating the mixture, the ammonium chloride will sublimate, leaving behind the sand, iron fillings, and sodium chloride.

3. Filtration: Filtration can be used to separate the remaining mixture of sand and sodium chloride. Since sand is insoluble in water and sodium chloride is soluble, we can dissolve the sodium chloride in water and then pass the mixture through a filter. The sand particles will be retained on the filter paper, while the sodium chloride solution will pass through as filtrate.

4. Evaporation: The final step involves separating the sodium chloride from the water. This can be achieved through evaporation. The sodium chloride solution obtained from filtration is heated, and as the water evaporates, sodium chloride crystals will start to form. Once all the water has evaporated, sodium chloride crystals can be collected.

Summary:
By employing the techniques of magnetic separation, sublimation, filtration, and evaporation, we can successfully separate the mixture of sand, iron fillings, ammonium chloride, and sodium chloride. The iron fillings are separated using a magnet, ammonium chloride is separated through sublimation, and the remaining mixture of sand and sodium chloride is separated by filtration. Finally, the sodium chloride is obtained by evaporating the water from the sodium chloride solution.