Class 11Chemistry3 Organic Chemistry: Purification and CharacterisationPurification of Organic Compounds
DifficultExplain distillation under reduced pressure.
(N/A) $(i)$ This method is used to purify liquids having very high boiling points.
$(ii)$ It is used for liquids that decompose at or below their boiling points.
Such liquids are made to boil at a temperature lower than their normal boiling points by reducing the pressure on their surface.
$A$ liquid boils at a temperature at which its vapour pressure is equal to the external pressure.
The pressure is reduced with the help of a water pump or vacuum pump.
Use: Glycerol can be separated from spent-lye in the soap industry by using this technique.
$(ii)$ It is used for liquids that decompose at or below their boiling points.
Such liquids are made to boil at a temperature lower than their normal boiling points by reducing the pressure on their surface.
$A$ liquid boils at a temperature at which its vapour pressure is equal to the external pressure.
The pressure is reduced with the help of a water pump or vacuum pump.
Use: Glycerol can be separated from spent-lye in the soap industry by using this technique.
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Given below are two statements:
Statement $I$: Vapours of the liquid with higher boiling point condense before vapours of the liquid with lower boiling points in fractional distillation.
Statement $II$: The vapours rising up in the fractionating column become richer in high boiling component of the mixture.
Statement $I$: Vapours of the liquid with higher boiling point condense before vapours of the liquid with lower boiling points in fractional distillation.
Statement $II$: The vapours rising up in the fractionating column become richer in high boiling component of the mixture.
What is $R_f$?
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Given below are two statements:
Statement $I$: $A$ mixture of $C_{12}H_{22}O_{11}$ (sugar) and $NaCl$ can be separated by dissolving sugar in alcohol, due to differential solubility.
Statement $II$: Rose essence from rose petals is separated by steam distillation due to its high volatility and insolubility in $H_2O$.
Statement $I$: $A$ mixture of $C_{12}H_{22}O_{11}$ (sugar) and $NaCl$ can be separated by dissolving sugar in alcohol, due to differential solubility.
Statement $II$: Rose essence from rose petals is separated by steam distillation due to its high volatility and insolubility in $H_2O$.
At what temperature and pressure does a liquid vaporize in steam distillation?
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