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प्रश्न
Differentiate between hydrated and anhydrous crystals with examples. State three defined changes that occur when hydrated copper sulphate is heated.
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उत्तर
Difference between hydrated and anhydrous crystals:
| Hydrated crystal | Anhydrous crystal |
| (i) Contains fixed number of water molecules. | (i) Does not contains any fixed number of water molecules |
| (ii) CuSO4, 5H2O, FeSO4.7H2O are examples. | KNO3, K2SO4 are examples. |
Three defined changes: When CuSO4. 5H2O is heated take place are: (blue).
- Colour changes from blue to colourless.
- Changed to AMORPHOUS white powder
- Geometric shape vanishes
- On cooling and adding water colour restores but crystalline does not shape.
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संबंधित प्रश्न
Define water of crystallization. Give two examples with formulae.
What do you observe when Blue vitriol is heated?
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:
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Common Name |
Chemical Name |
Formula |
Acid, base or salt |
Efflorescent, hygroscopic or deliquescent substance |
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Solid caustic potash |
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Quick lime |
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Oil of vitriol |
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Washing soda |
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Solid caustic soda |
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Blue vitriol |
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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 ‘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.
Explain the following observation:
In the expression anhydrous copper sulphate, what is meant by “anhydrous”?
Explain the following observation:
Why is fused calcium chloride or cone, sulphuric acid used in a desiccator?
Give a reason for the following:
Heating a hydrated copper sulphate crystal is deemed a chemical change.
A hot saturated solution of copper sulphate forms crystals as it cools. Why?
