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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
Define water of crystallization. Give two examples with formulae.
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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Name three methods by which hydrous substances 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.
Differentiate the function of concentrated sulphuric acid as a drying agent & as a dehydrating agent. Is fused calcium chloride a dehydrating or a desiccating agent. Give reasons.
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 |
Select the correct answer from the choice given in the options.
An anhydrous crystal _____.
Differentiate between the following:
Deliquescent salt and hygroscopic 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.
