What Is The Principle Of Fractional Distillation

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It is the process of which the separation of a mixture of various components such as chemical compounds by using their boiling points by heating them to a temperature where they will be easily evaporated and forms different fractions. It also requires standard atmospheric pressure to be carried out in this operation.


The principle of this distillation process is based on the difference of boiling points between the mixtures of two substances which is being used for the distillation. As the substances have different boiling points. So, with the passage of heat different impurities show different boiling point and separated easily with the help of outlet pipe.

For example, consider the distillation of a mixture of water and ethanol. Ethanol boils at 78.5 °C, and water boils at 100 °C. On that basis, one should be able to separate the two components by fractional distillation. However, a mixture of 96 percent ethanol and four percent water boils at 78.2 °C, being more volatile than pure ethanol. Such a mixture is called an azeotrope. When the mixture is gently heated, the azeotrope (being the most volatile component) concentrates to a greater degree in the vapor and separates from the rest of the liquid first. Thus, fractional distillation of a mixture of water and ethanol produces 96 percent ethanol. ]Once all the ethanol has boiled out of the mixture, the thermometer shows a sharp rise in temperature.


A laboratory setup for fractional

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