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प्रश्न
Differentiate between ‘hydrated’ & ‘anhydrous’ crystals. Give the chemical formula of – the following hydrated crystals -
(a) Washing soda
(b) Gypsum
(c) Blue vitriol
(d) Epsom salt
(e) Glauber’s salt.
State which crystal from (a) to (e) is a pentahydrate.
उत्तर
| Hydrated crystals | Anhydrous crystals |
| Hydrated crystals contain a definite number of water molecules (as water of crystallisation) in a loose chemical combination with the crystal. | Anhydrous crystals do not contain any definite number of water molecules in loose chemical combinations with the crystal. |
| E.g., CuSO4.5H2O | E.g., KNO3 |
The formula of hydrated crystals:
(a) Washing soda: Na2CO3.H2O
(b) Gypsum: CaSO4.2H2O
(c) Blue vitriol: CuSO4.5H2O
(d) Epsom salt: MgSO4.7H2O
(e) Glauber’s salt: Na2SO4.10H2O
Blue vitriol [CuSO4.5H2O] is a pentahydrate.
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संबंधित प्रश्न
Give two examples of Crystalline anhydrous substances.
Give two examples for Deliquescent substance.
What do you observe when Blue vitriol is heated?
Water turns the colour of anhydrous copper sulphate .................
Complete the following table:
|
Common Name |
Chemical Name |
Formula |
Acid, base or salt |
Efflorescent, hygroscopic or deliquescent substance |
|
Solid caustic potash |
|
|
|
|
|
Quick lime |
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|
|
|
|
Oil of vitriol |
|
|
|
|
|
Washing soda |
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|
|
Solid caustic soda |
|
|
|
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Blue vitriol |
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|
State the methods by which hydrated salts can be made anhydrous.
Name three methods by which hydrous substances 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.
Differentiate between an efflorescent, deliquescent & ‘ hygroscopic substance with suitable examples.
Give a reason for the following:
Heating a hydrated copper sulphate crystal is deemed a chemical change.
