Question

What is the function of the fractionating column?
A) To separate the two components
B) To provide greater cooling surface to the vapors
C) To keep the vapor pressure constant
D) To avoid the mixing of the vapors of two components.

Answer 1

Hint:Fractionating column is a part of a process known as fractional distillation. Fractional distillation is a process where two or more liquid mixtures with small differences in their volatility are separated. In this process the liquids undergo continuous distillation and condensation.


Complete solution:
Let us understand the process of fractional distillation first. Fractional distillation as the name suggests is the separation of liquids in or as fractions. In this process the mixture of liquids is heated such that the liquids start to vaporize at their respective boiling points and those fractions are separated.
This way, we can understand that liquids with lower boiling points will be separated first and liquids with significantly higher boiling points are separated last.
Fractional distillation consists of a burner, round bottomed flask, condenser, fractionating column and a thermometer.A burner is used to heat the mixture to acquire the boiling points of the liquids present in the mixture.A round bottomed flask is used to contain the mixture when it is being heated. The evaporated liquids travel through this round bottomed flask and into the fractionating column.
The fractionating column then separates the evaporated liquids and transports them to a condenser where they are cooled back to liquids. Therefore, the function of the fractionating column is to separate two components.

Therefore,the correct option is (A).


Note: A fractionating column is fitted with glass beads to increase the surface area through which the evaporated liquids travel. This enables better separation of the liquids. If the boiling points of the liquids are extremely close then the length of the fractionating column should be more.