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प्रश्न
Explain the following observation:
Why is fused calcium chloride or cone, sulphuric acid used in a desiccator?
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उत्तर
Anhydrous or fused calcium chloride is highly hygroscopic in nature it readily absorbs moisture, also it is deliquescent in nature and is therefore used as a drying agent in a desiccator.
Concentrated sulphuric acid being hygroscopic in nature absorbs moisture from the air and gets diluted and acts as a drying agent as well as a dehydrating agent and hence is used in a desiccator.
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संबंधित प्रश्न
Water turns the colour of anhydrous copper sulphate .................
Give one word for the following statement:
A substance which does not contain water .
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.
Complete the statement by filling the blank with the correct word from the option.
Hygroscopic substance absorb moisture from the atmosphere & _______their original state.
Match the substances in List I with the appropriate answer in List II.
| List I | List II |
| 1. Green vitriol | A: Permanent hardness in water |
| 2. Paint | B: Hygroscopic |
| 3. Magnesium chloride | C: Temporary hardness in water |
| 4. Magnesium bicarbonate | D: Heptahydrate |
| 5. Calcium oxide | E: Colloidal |
Differentiate between hydrated and anhydrous crystals with examples. State three defined changes that occur when hydrated copper sulphate is heated.
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.
'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.
What happens when MgSO4.7H2O is heated? Write the appropriate equation?
