Is Matter Around Us Pure — Science STD 9 — Question
Gujarat BoardEnglish MediumSTD 9ScienceIs Matter Around Us Pure1 Mark
MCQ
To separate ammonium chloride from common salt, we use:
A
Filtration
B
Sedimentation
C
Sieving
✓
Sublimation
✓
Answer
Correct option: D.
Sublimation
Sublimation is a method in which a solid substance directly changes to the gas phase without changing into the liquid phase.
Ammonium chloride is separated from common salt$($sodium chloride$)$ by sublimation.
This happens because ammonium chloride is volatile in nature whereas common salt is non$-$volatile in nature.
Hence when a mixture of ammonium chloride and common salt is heated, ammonium chloride changes its state from solid to vapour.
The vapours of ammonium chloride are then condensed on a cold surface.
The common salt$($sodium chloride$)$ is left behind.
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