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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
Give one word for the following statement:
A substance which does not contain water .
Give one word for the following statement:
Water molecules in loose chemical combination with other substances.
Give the names and formulae of two substances
Anhydrous substance
The substance that can remove hydrogen and oxygen atoms in the ratio of 2:1(in the form of water) from the compound.
What are drying or desiccating agents? Give examples.
State the methods by which hydrated salts can be made anhydrous.
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.
Match the following
| 1. | Blue vitriol | CaSO4.2H2O |
| 2. | Gypsum | CaO |
| 3. | Deliquescence | CuSO4.5H2O |
| 4. | Hygroscopic | NaOH |
Define Hydrated salt.
'A' is a blue coloured crystalline salt. On heating, it loses blue colour and to give 'B'. When water is added, 'B' gives back to 'A'. Identify A and B, write the equation.
