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प्रश्न
Define the following term:
Efflorescence
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उत्तर
It is the phenomenon by which hydrated salts, on exposure to dry air, lose their water of crystallization and crumble to powder.
संबंधित प्रश्न
Identify the substance underlined, in the following case
A solid formed by reaction of two gases, one of which is acidic and the other basic in nature
Which of the following salt has a blue colour and why?
CuSO4.5H2O or CuSO4
Name three chemicals made from common salt (or sodium chloride).
Common salt is obtained from sea-water by the process of ______.
How would you show that blue copper sulphate crystals contain water of crystallisation?
The aqueous solution of one of the following salts will turn red litmus to blue. This salt is:
The metal salt A is blue in colour. When salt A is heated strongly over a burner, then a substance B is eliminated and a white powder C is left behind. When a few drops of a liquid D are added to powder C, it becomes blue again. What could be A, B, C and D?
Give one example of a salt which gives an aqueous solution having:
pH less than 7
Name a salt whose solubility decreases with temperature.
Define the following term:
Hygroscopy
Taking sodium carbonate as an example, give the meaning of the following terms:
Water of crystallization
Distinguish by a chemical test sodium carbonate and sodium sulphite.
Write any five uses of salts.
The Salt Story
From: The New Indian Express 9 March 2021
The salt pans in Marakkanam, a port town about 120 km from Chennai are the third largest producer of salt in Tamil Nadu. Separation of salt from water is a laborious process and the salt obtained is used as raw materials for manufacture of various sodium compounds.
One such compound is Sodium hydrogen carbonate, used in baking, as an antacid and in soda acid fire extinguishers.
The table shows the mass of various compounds obtained when 1litre of sea water is evaporated.
| COMPOUND | FORMULA | MASS OF SOLID PRESENT /g |
| Sodium Chloride | NaCl | 28.0 |
| Magnesium Chloride | MgCl2 | 8.0 |
| Magnesium Sulphate | MgSO4 | 6.0 |
| Calcium Sulphate | CaSO4 | 2.0 |
| Calcium Carbonate | CaCO3 | 1.0 |
| TOTAL AMOUNT OF SALT OBTAINED | 45.0 | |
How many grams of Magnesium Sulphate are present in 135g of solid left by evaporation of sea water?
Acids react with metallic oxides to produce ______.
Salt which is formed by the partial replacement of hydrogen ions of an acid by a metal is called ______.
What are hygroscopic substances?
You are provided with the list of chemicals mentioned below in the box:
| Sodium hydroxide solution, copper carbonate, zinc, hydrochloric acid, copper, dilute sulphuric acid, chlorine, iron |
Using suitable chemicals from the list given, write a balanced chemical equation for the preparation of the salt mentioned below:
Copper sulphate
