In a vacuum distillation the boiling point of glycerin is reduced to _?
Correct answer: D. 210°C
- A. 290°C
- B. 110°C
- C. 156°C
- D. 210°C
Explanation
Correct option is D. Under vacuum, the boiling temperature of glycerin decreases to 210°C at 50 torr. It is distilled at this temperature without decomposition for purification. Vacuum distillation is the distillation carried on under reduced pressure so that the liquid being distilled boils at a lower temperature than under atmospheric pressure and consequently with less chance of decomposition compared to molecular distillation.
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About Sublimation and Distillation
Sublimation separates a sublimable solid from non-sublimable impurities by direct conversion between solid and vapour, followed by deposition. Distillation separates liquids through differences in boiling points, including simple, fractional, steam and vacuum distillation, and the choice depends on volatility, miscibility and thermal stability.
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