Test: Separation Of Liquid Mixtures - Class 9

Fractional distillation is a process to separate the different components in a mixture based on the different boiling points of the components. 


Inside the furnace, the oil is heated to about 400ºC, at which it vaporizes and passes up the fractionating column. The components or fractions condense and exit the column at different heights depending on their boiling points. 

The difference in the boiling point of the liquids is less than 30° C . Water is a universal solvent. Both ethyl alcohol and water are liquids .

This method is used to separate the mixture of two miscible liquids where difference between their boiling points is less than 25 ºC. Also to separate a mixture of two or more miscible liquids for which the difference in boiling points is less than 25 K, fractional distillation process is used, for example, for the separation of different gases from air, different factions from petroleum products etc. The apparatus is similar to that for simple distillation, except that a fractionating column is fitted in between the distillation flask and the condenser. A simple fractionating column is a tube packed with glass beads. The beads provide surface for the vapours to cool and condense repeatedly, as shown in following figure.

Separation by a separating funnel : 
A mixture of two immiscible liquids can be separated by using a separating funnel. A separating funnel is a special type of funnel which has a stop-cock in its stem to allow the flow of a liquid from it, or to stop the flow of liquid from it. The separation of two immiscible liquids by a separating funnel depends on the difference in their densities.

Filtration is any of various mechanical, physical or biological operations that separate solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass. The fluid that passes through is called the filtrate