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प्रश्न
Give a brief description of the principle of the following technique taking an example.
Distillation
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उत्तर
Distillation is used to separate volatile liquids from non-volatile impurities or a mixture of those liquids that have a sufficient difference in their boiling points.
Principle:
It is based on the fact that liquids having different boiling points vapourise at different temperatures. The vapours are then cooled and the liquids so formed are collected separately.
For example, a mixture of chloroform (b.p = 334 K) and aniline (b.p = 457 K) can be separated by the method of distillation. The mixture is taken in a round bottom flask fitted with a condenser. It is then heated. Chloroform, being more volatile, vaporizes first and passes into the condenser. In the condenser, the vapours condense and chloroform trickles down. In the round bottom flask, aniline is left behind.
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संबंधित प्रश्न
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Match the type of mixture of compounds in Column I with the technique of separation/purification given in Column II.
| Column I | Column II |
| (i) Two solids which have different solubilities in a solvent and which do not undergo reaction when dissolved in it. | (a) Steam distillation |
| (ii) Liquid that decomposes at its boiling point | (b) Fractional distillation |
| (iii) Steam volatile liquid | (c) Simple distillation |
| (iv) Two liquids which have boiling points close to each other | (d) Distillation under reduced pressure |
| (v) Two liquids with large difference in boiling points. | (e) Crystallisation |
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