Just like solids, liquids can be impure. They can be removed through different methods according to their properties. Do you know what these methods are? In this lesson, we will be learning about these methods. Lesson on how solids are separated is previously discussed.
These methods involve:
Separating Funnel
Simple Distillation
Fractional Distillation
Explanation:
To remove two liquids which are immiscible, we use a separating funnel. Immiscible liquids are those which don't dissolve in each other. We pour the denser liquid first and then the less dense liquid. For example the layer of oil on the layer of water. Place the funnel on the beaker and then on the tap. The first layer of liquid will be obtained in the beaker. Stop the tap so that the second layer won't run out. Collect it in another beaker. Hence, in this way one can separate immiscible liquids.
Liquids which are miscible can be separated through fractional distillation. Miscible liquids are those which dissolve in each other, just like ethanol and water. Ethanol and water are heated in a round bottom flask with attached condenser and thermometer. Thermometer measures the temperature of the vapors and the condenser changes the vapors into water. The liquid with lower boiling point, evaporates first and is then condensed and collected in a conical flask. Fractionating column attached has glass beads which gives a huge surface area for the vapours. It only allows the liquid with lower boiling point to evaporate first. If the liquid is volatile, then put the flask in an ice bath to maintain its state. Volatile liquids are those which evaporate at room temperature. When liquid with lower melting point is collected in the beaker then temperature rapidly rises which tells us that the liquid is separated from the solution. The other liquid is obtained in the round bottom flask.
We can also remove liquids from the solution of liquid and solid. This method is similar to fractional distillation and is known as simple distillation. The apparatus is the same, only a fractionating column is not required. The liquid evaporates due to the heat provided. It is cooled down when it passes through the condenser and is collected in the beaker as a distillate. Solute is there in the round bottom flask.
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