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| Laboratory Preparation of Ammonia |
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| For use in the laboratory, ammonia is prepared by heating an ammonium salt with a strong base. It can also be prepared by reacting a metal nitride with water. All ammonium salts heated with alkali evolve ammonia. Ammonium nitrate is not used in laboratory preparation, since it is explosive in nature and may decompose forming nitrous oxide and water vapour. |
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| Ammonia is prepared in the laboratory by heating a mixture of solid ammonium chloride and calcium hydroxide. |
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| Reactants |
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| Ammonium chloride and calcium hydroxide, Ratio 2:3 |
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| Procedure |
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| Ammonium chloride and calcium hydroxide are ground together and heated slowly in a round bottomed flask with its neck sloping downwards. The gas is passed through a drying tower before collection. |
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| Drying agent |
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| Quicklime. (CaO). Quicklime being basic in nature does not react with basic ammonia gas. But absorbs moisture |
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| (CaO + H2O g Ca(OH)2) |
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| Collection |
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| Ammonia gas is lighter than air and hence collected by the downward displacement of air. It is not collected over water since it is highly soluble in water. |
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