The easiest way to separate common salt and ammonium chloride from a mixture is through the process of sublimation.
Sublimation is the process in which a solid substance is directly converted to the gaseous phase, without the intermediate liquid phase. Camphor is a common example of a substance that undergoes sublimation. Similarly, ammonium chloride undergoes sublimation. When ammonium chloride is heated, it gets converted into ammonia and hydrochloric acid. The chemical reaction of this process can be written as:
`NH_4Cl (s) -> NH_3 (g) + HCl (g)`
Common salt (also known as sodium chloride), on the other hand, does not undergo sublimation.
Thus, if we heat a mixture of ammonium chloride and common salt, the former will convert to the gaseous phase, while the common salt will be left over as solid. The gases can be collected and cooled to obtain ammonium chloride; thus obtaining the two salts separately.
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