Question

State the technique used for separating the following mixture:
Petrol from crude oil

Answer 1

Fractional distillation

Principle: This process works on the basis of differences in the boiling points of different miscible liquids.

• Miscible liquids can be separated by the process of thermometer fractional distillation.
• The separation of mixture of liquids by distillation is called fractional distillation.
• This is based on the principle that different liquids have different boiling points.
• A mixture of alcohol and water can be separated by fractional distillation.
• Alcohol has a lower boiling point than water and therefore evaporates first.
• The vapor of alcohol get condensed in the condenser and alcohol is collected in the flask.
• Water having a higher boiling point is left behind in the distillation flask. This technique is used when the difference between boiling points of two liquids is 25°C or more.
• Petrol, diesel and kerosene are obtained from crude petroleum by the process of fractional distillation.