Different Separation methods
When you carry out a reaction, you usually end up with a mixture of substances. Then you have to separate the one you want. Today, we are going to talk about different methods of separating different mixtures.
Simple distillation
With the help of this process. we can obtain a solvent form a solvent.
Diagram for Simple distillation is shown below. This process can be used to extract pure water from the salt-water. This can be done in the following way:
1: The salt-water solution in the flask is heated. When it starts boiling, the water vapours start to rise and this condenses in lie beg condenser.
2: Since the condensers is cold, it condenses the vapours back into water.
3: The condensed water now drips into the beaker for collection, this water is pure.
Fractional distillation
The fractional distillation is used to separate two liquids that are miscible, it separates them based on their boiling points, since liquids in mixtures have different boiling points. For example, water and ethanol can be separated by using this method.
These are the steps:
1: First of all, heat the mixture in the conical flask. As the temperature rises to 78 degree Celsius, ethanol vapours begin to rise since 78 degree Celsius is the boiling point of ethanol. Along with ethanol vapours, some water vapours also rise up. A mixtures of vapours from ethanol and water rises up the fractionating column.
2: The glass beads in the fractionating column condenses the vapours which makes the glass beads hot.
3: After some time, the temperature of the glass beads reaches 78 degree Celsius, now, the ethanol vapours will not condense but the water vapour will condense and fall back in to the flask. ethanol vapour eventually reaches the condenser.
4: Lie beg condenser condenses the ethanol vapours back to liquid and this liquid is then collected in the beaker.
5: After some time, the reading on the thermometer will rapidly rise past 78 degree Celsius, this means that all the ethanol present in the mixture is being used up.
Use of Fractional Distillation in the Industries
This method of separation plays a vital role in the industries. For example it is used:
- In the petroleum industry, the crude oil is heated and different fractions of it rises up the fractionating column based on their boiling points.
- In ethanol production. Ethanol, which is made by fermentation, is being separated from the mixture by fractional distillation. It is also used as solvent to absorb organic compounds and cars can also make use of ethanol.
- In the separation of different gases present in air. We can obtain Nitrogen Hydrogen for the Haber process with the help of fractional distillation.
Paper chromatography
Many mixtures of substances can be separated by this method. We can find the number of dyes present in ink.
2: Afterwards, we add some water on the ink spot. the inks spots results in several color circles which spread out.
Different dyes have different solubilities and based on this fact, they travel at a rate different from each other. (The faster it travel the more soluble dye is)
This is the reason behind why colour rings are formed. We call this paper with rings of dyes a chromatogram.
This method can also be used to determine different substances. For
example, mixture X is thought to contain substances A, B, C, and D,
which are all soluble in propanone. You could check the mixture like this:
3: X has separated into three spots.
Two are at the same height as A and
B, so X must contain substances A
and B. Does it also contain C and D?
Note that you must use a pencil to draw the line on the chromatography
paper. If you use a biro or felt-tipped pen, the ink will run.
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