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प्रश्न
Name three methods by which hydrous substances can be made anhydrous.
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उत्तर
Three methods by which hydrous substances can be made anhydrous are:
- Heating under vacuum.
- Direct heating.
- Heating in dry or hot air.
- By using dehydrating/desiccating agents such as warm concentrated sulphuric acid.
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संबंधित प्रश्न
Define water of crystallization. Give two examples with formulae.
What do you observe when Blue vitriol is heated?
Water turns the colour of anhydrous copper sulphate .................
Give the names and formulae of two substances.
Hydrated substance
Give the names and formulae of two substances
Anhydrous substance
What are hydrous substances? Explain with examples.
Match the substances in List I with the appropriate answer in List II.
| List I | List II |
| 1. Green vitriol | A: Permanent hardness in water |
| 2. Paint | B: Hygroscopic |
| 3. Magnesium chloride | C: Temporary hardness in water |
| 4. Magnesium bicarbonate | D: Heptahydrate |
| 5. Calcium oxide | E: Colloidal |
Explain the following observation:
Why is fused calcium chloride or cone, sulphuric acid used in a desiccator?
Differentiate between hydrated and anhydrous crystals with examples. State three defined changes that occur when hydrated copper sulphate is heated.
'A' is a blue coloured crystalline salt. On heating, it loses blue colour and to give 'B'. When water is added, 'B' gives back to 'A'. Identify A and B, write the equation.
