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General Preparation of Salts |
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Salts are generally ionic compounds formed by the reaction of an acid with a base. The preparation of these salts involves the treating of different metals and non-metals and their compounds with various acids, bases etc. However, some of them can be prepared by direct combination of the concerned elements or also by indirect routes. |
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Preparation of Certain Salts in the Laboratory |
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Preparing Zinc Sulphate
Take zinc granules in a beaker and dissolve them in dilute sulphuric acid. The zinc granules must be in excess. Effervescence of hydrogen gas appears immediately. Wait till the effervescence is over.
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Preparation of Sodium Bicarbonate |
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Pass carbon dioxide through a solution of sodium carbonate for some time. Evaporate the resulting solution to dryness whereby sodium bicarbonate crystals separate out. |
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Preparation of Potassium Bicarbonate |
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Pass carbon dioxide through a solution of potassium carbonate for some time. Evaporate the resulting solution to dryness when potassium bicarbonate crystals separate out. |
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Water of crystallization |
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Water of crystallisation is a definite molecular proportion of water molecules, chemically combined to a salt in the crystalline state. This water of crystallisation is responsible for the geometric shape and colour of the crystals i.e., for the crystalline appearance of a salt. |
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Summary |
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Efflorescent substances are those, which lose water of crystallization to the atmosphere and crumble into powder. |
