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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.
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
Water turns the colour of anhydrous copper sulphate .................
Give the names and formulae of two substances
Anhydrous substance
What are drying or desiccating agents? Give examples.
Complete the following table:
|
Common Name |
Chemical Name |
Formula |
Acid, base or salt |
Efflorescent, hygroscopic or deliquescent substance |
|
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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State the methods by which hydrated salts can be made anhydrous.
What are hydrous substances? Explain with examples.
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 between the following:
Deliquescent salt and hygroscopic salt
Match the following
| 1. | Blue vitriol | CaSO4.2H2O |
| 2. | Gypsum | CaO |
| 3. | Deliquescence | CuSO4.5H2O |
| 4. | Hygroscopic | NaOH |
