Understanding the Properties
* Solubility: Ammonium chloride is more soluble in water than salt. This means it dissolves more readily.
* Sublimation: Ammonium chloride can sublimate (change directly from solid to gas) when heated gently. Salt does not.
Separation Methods
1. Sublimation:
* Procedure:
1. Carefully heat a mixture of ammonium chloride and salt in a beaker or evaporating dish.
2. The ammonium chloride will sublime, leaving behind solid salt.
3. Collect the sublimed ammonium chloride on a cool surface (like the bottom of an inverted funnel) placed above the heating vessel.
* Note: Sublimation requires careful temperature control to avoid decomposition of ammonium chloride.
2. Selective Dissolution:
* Procedure:
1. Dissolve the mixture in a minimal amount of hot water.
2. The ammonium chloride will dissolve completely, while most of the salt will remain undissolved.
3. Filter the solution to remove the undissolved salt.
4. Evaporate the water from the filtrate to recover the ammonium chloride as a solid.
* Note: This method may not completely separate the salt, as some salt will dissolve in the water.
Choosing the Best Method
* Sublimation: This is the most effective method for separating ammonium chloride and salt. It allows for a clean separation, but requires careful temperature control.
* Selective Dissolution: This method is simpler and requires less specialized equipment but may result in some salt contamination in the final ammonium chloride product.
Safety Precautions
* Sublimation: Use a fume hood to avoid inhaling ammonium chloride fumes.
* Selective Dissolution: Use caution when handling hot water.
Additional Considerations
* The purity of the final product depends on the chosen method and the precision of the procedure.
* If high purity is required, a combination of both methods may be used.
