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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.
APPEARS IN
संबंधित प्रश्न
Give two examples for Deliquescent substance.
Water turns the colour of anhydrous copper sulphate .................
Give one word for the following statement:
A property due to which a substance absorbs water without dissolving.
What are drying or desiccating agents? Give examples.
Complete the following table:
|
Common Name |
Chemical Name |
Formula |
Acid, base or salt |
Efflorescent, hygroscopic or deliquescent substance |
|
Solid caustic potash |
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Quick lime |
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|
|
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Oil of vitriol |
|
|
|
|
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Washing soda |
|
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|
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Solid caustic soda |
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Blue vitriol |
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|
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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 |
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.
Give a reason for the following:
Heating a hydrated copper sulphate crystal is deemed a chemical change.
What happens when MgSO4.7H2O is heated? Write the appropriate equation?
