maa'm can u please explain me the fractional distillation//?????

Asked by  | 8th Mar, 2008, 09:32: PM

Expert Answer:

Separation by fractional distillation.
This method is used in the case of miscible liquids. We should know the meaning of miscible liquids which means those liquids which mix together in all proportions and form a single layer. Some of the common examples are alcohol and water, water and acetone, water and vinegar.

We should also know that there is difference in simple distillation and fractional distillation. The difference is that simple distillation is used for the separation of components of mixture containing two miscible liquids that boil without decomposition and have sufficient difference in their boiling points whereas fractional distillation is used to separate a mixture of two or more miscible liquids for which the difference in boiling points is less than 25 K.

A fractionating column which is a large vertical glass tube filled with glass beads. The glass beads provide a long surface area for hot vapours to cool and condense repeatedly. In this, different temperature zones are created, the highest temperature being at the bottom of the column and the lowest temperature near its top.

Alcohol and water are miscible liquids. We can separate this mixture by fractional distillation because boiling point of alcohol is 78oC and of water is 100oC .



Answered by  | 20th Dec, 2017, 04:51: PM