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Physical and Chemical Changes — Science STD 7 — Question

Gujarat BoardEnglish MediumSTD 7SciencePhysical and Chemical Changes1 Mark
MCQ
Vacuum desiccator is used $........:$
  • ✓
    For drying crystals
  • B
    For purifying crystals
  • C
    For separation of crystals
  • D
    For the process of crystallisation
✓

Answer

Correct option: A.
For drying crystals
Desiccators are an economical and reliable way to assure dry, dust$-$free storage and organization of humidity$-$sensitive products valuable reagents in crystalline form. Proper storage conditions can be optimized by selecting a desiccator size, shape, and control mechanism best suited for the application.
The lower compartment of the desiccator contains lumps of silica gel, anhydrous calcium chloride to absorb water vapor. The substance needing the desiccation is put in the upper compartment, on a glazed perforated ceramic plate. The ground glass rim of the desiccator lid must be greased with a thin layer of vacuum grease.

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