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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
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 |
|
|
|
|
|
Quick lime |
|
|
|
|
|
Oil of vitriol |
|
|
|
|
|
Washing soda |
|
|
|
|
|
Solid caustic soda |
|
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|
|
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Blue vitriol |
|
|
|
|
State the methods by which hydrated salts can be made anhydrous.
Differentiate between an efflorescent, deliquescent & ‘ hygroscopic substance with suitable examples.
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.
Match the following
| 1. | Blue vitriol | CaSO4.2H2O |
| 2. | Gypsum | CaO |
| 3. | Deliquescence | CuSO4.5H2O |
| 4. | Hygroscopic | NaOH |
The molecular formula of green vitriol is MgSO4.7H2O.
Define Hydrated salt.
What happens when MgSO4.7H2O is heated? Write the appropriate equation?
