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प्रश्न
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.
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उत्तर
Sulphuric acid (cone.) acts as drying agent when it removes water from other substances i.e. for drying gases.
Cone, sulphuric acid acts as dehydrating agent when it removes chemically combined water from compounds due to it strong affinity for water.
\[\ce{\underset{\text{ethanol}}{C2H5OH} + ->[Conc. H2SO4][dehydrating agent] \underset{\text{ethene}}{C2H4} +\underset{\text{water}}{H2O}}\]
Cone. H2SO4 has removed H20 from ethanol and changed it to ethene. Fused calcium chloride [CaCl2] is desiccating agent as it is drying the substance.
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संबंधित प्रश्न
Give two examples of Crystalline anhydrous substances.
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.
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 _____.
Name or state the following:
A liquid hydroscopic substance.
The molecular formula of green vitriol is MgSO4.7H2O.
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.
