Have you heard of distilled water filling up in batteries? Is it the same drinking water or different?
Do you like traveling?
Travel is an important aspect of our lives. All of it, be it day-to-day travel or trips between cities or countries, is made possible by automobiles, aircraft, etc., and all of them require fuel like petrol, diesel, etc.
These fuels are manufactured from crude oil by a process called fractional distillation. Crude oil is heated and, after putting it in the distillation column, it is separated into different liquids and gases.
By the fractional distillation of crude oil, various products like butane, propane, petrol, kerosene, diesel, fuel oil are produced.
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Distillation is a simple physical separation method based on the difference in boiling temperatures of the components of a solution. The solution is heated at a selective boiling temperature that forces one of the components to enter the gaseous phase and is thus separated from the solution. This vapour-phased component is further condensed and collected separately.
By this process, non-volatile impurities and also liquids having a sufficient difference in boiling points are separated from volatile liquids.
On heating, a liquid starts converting into its vapour phase at its boiling point. It involves heating a liquid to generate vapour and then cooling it to return it to its liquid state.
On heating, at a particular temperature, when the vapour pressure of a liquid becomes equal to the external (atmospheric) pressure, the liquid starts boiling, and this temperature is known as the boiling point of a liquid.
The boiling point of a liquid varies with the external (atmospheric) pressure. The boiling point is different for different liquids and is characteristic of the chemical nature of the substance.
The distillation of a mixture of liquids depends on Raoult’s law and Dalton's law.
According to Dalton’s law of partial pressures, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of all the constituent gases.
As per Raoult’s law, the partial pressure of a liquid component in an ideal liquid mixture equals the product of the vapour pressure of the pure component and its mole fraction in the liquid mixture.
Fractional distillation is widely used to separate mixtures of liquids having similar or close boiling points. Several steps of vaporization-condensation are involved (which take place in a fractionating column). The fractional distillation equipment is quite complex and consists of the following components:
The vacuum distillation technique is employed for chemicals that are sensitive to air and react quickly with it, but the vacuum must be replaced with an inert gas after the procedure is completed. This type of procedure is known as air-sensitive vacuum distillation.
At high temperatures, short-path distillation is used to purify a small amount of a volatile chemical. This is done at lower pressures, and the distillate is usually recovered after a short journey (thus the name "short path"). As a result, the distillate travels a shorter distance, resulting in less loss along the apparatus's walls.
The technique of partially melting a substance and then condensing the resulting vapours to obtain a pure distillate is known as zone distillation. This is done in a long container with the help of a zone heater.
Q 1. Which two processes are involved in distillation?
a. Freezing and condensing
b. Distilling and condensing
d. Only condensation
Distillation involves the two processes of distilling and condensing, which are carried out in a distillation column.
Q 2. Distillation is discovered by which scientist?
a. Guldberg and Waage
b. Charles Chamberland
c. Clarence Birdseye
d. Jabie ibn hayyan
Distillation was discovered by Jabie ibn hayyan.
Q 3. For which process double distillation is used?
a. Coffee for commercial uses
b. Wine for commercial uses
c. Distilled water for laboratory purposes
d. Distilled water for commercial use.
Flaks with heating elements are used in double distillation. In addition to providing for reflux distillation, it is employed to carry out reactions under stirring conditions. It's used to make distilled water for lab experiments.
Q 4. Which factors affect distillation?
a. Relative volatility
b. Surface area
d. All of these
There are various factors that affect the distillation process, which are solubility, relative volatility, and activity coefficient, and it also depends on the surface area.
Q 5. MaCabe-Thiele plot is explained for which process?
c. Molecular separation
The distillation process is used to explain the distillation process. This plot is used for binary mixtures to calculate the number of theoretical trays required for the distillation process.
Q 1. Why are plastic beads used in fractional distillation?
Answer: Plastic beads or steel wool are used to increase the surface area, which improves the separation between liquids being distilled.
Q 2. Give an example for which the triple distillation method is used?
Answer: Triple distillation method is used for the manufacturing of smooth whiskies.
Q 3. Give one application of steam distillation?
Answer: To obtain essential oils from aromatic flowers
Q 4. How does the boiling point of a liquid vary with pressure?
Answer: The boiling point of a liquid is a temperature at which the vapour pressure of a liquid becomes equal to atmospheric pressure, so when atmospheric pressure changes, the boiling point of a liquid also changes.
Q 5. Which distillation techniques are used for the molecules having very little difference in boiling points?
Answer: Fractional distillation is used to separate those liquids which have fewer differences in boiling points.