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प्रश्न
Name three methods by which hydrous substances can be made anhydrous.
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.
Give two examples for Deliquescent substance.
Give one word for the following statement:
Water molecules in loose chemical combination with other substances.
Give the names and formulae of two substances.
Hydrated substance
The substance that can remove hydrogen and oxygen atoms in the ratio of 2:1(in the form of water) from the compound.
Complete the following table:
|
Common Name |
Chemical Name |
Formula |
Acid, base or salt |
Efflorescent, hygroscopic or deliquescent substance |
|
Solid caustic potash |
|
|
|
|
|
Quick lime |
|
|
|
|
|
Oil of vitriol |
|
|
|
|
|
Washing soda |
|
|
|
|
|
Solid caustic soda |
|
|
|
|
|
Blue vitriol |
|
|
|
|
State the methods by which hydrated salts can be made anhydrous.
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.
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.
