Question

Write short note on following:

Fractional distillation

Answer 1

Different separation techniques are present depending on the property of the substances to be separated.

Fractional distillation

• Miscible liquids having boiling point difference less than ${25}^{\mathrm{o}}\mathrm{C}$ separated using fractional distillation.
• The main difference between simple distillation and fractional distillation is the presence of fractionating column (glass beads packed in the tube).
• This provide increased surface area for continuous evaporation and condensation.
• The mixture is heated in a distillation flask, the liquid gets vaporised and condensed and one with a higher boiling point falls into the distillation flask, and one with lower boiling point pass through the condenser and collected in the receiver.
• After this, when the temperature increases, liquid with a higher boiling point rises, condenses, and collected.
• Mixture of alcohol (boiling point $78.5^{\mathrm{o}}\mathrm{C}$) and water (${100}^{\mathrm{o}}\mathrm{C}$) separated using this technique.
• Below picture shows setup for fractional distillation