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प्रश्न
Select the correct word from the words in option to complete the sentence:
Efflorescence occurs when the vapour pressure of the hydrated crystals is ____ than the vapour pressure of the atmospheric humidity.
विकल्प
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उत्तर
Efflorescence occurs when the vapour pressure of the hydrated crystals is more than the vapour pressure of the atmospheric humidity.
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संबंधित प्रश्न
Define water of crystallization. Give two examples with formulae.
Water turns the colour of anhydrous copper sulphate .................
Give one word for the following statement:
A substance which does not contain water .
Give the names and formulae of two substances.
Hydrated substance
What are hydrous substances? Explain with examples.
The process of separation or deposition of crystals from a hot saturated solution on gentle cooling of the solution is called ‘crystallization’. With reference to the statement explain what is meant by ‘water of crystallization. State which physical properties of a crystal are correlated with the water of crystallization.
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:
In the expression anhydrous copper sulphate, what is meant by “anhydrous”?
Differentiate between hydrated and anhydrous crystals with examples. State three defined changes that occur when hydrated copper sulphate is heated.
Match the following
| 1. | Blue vitriol | CaSO4.2H2O |
| 2. | Gypsum | CaO |
| 3. | Deliquescence | CuSO4.5H2O |
| 4. | Hygroscopic | NaOH |
