JEE MainChemistryThermodynamicsMCQ+4 / −1
The entropy change associated with the conversion of 1 kg of ice at 273 K to water vapours at 383 K is : (Specific heat of water liquid and water vapour are 4.2 kJ K 1 kg 1 and 2.0 kJ K 1 kg 1; heat of liquid fusion and vapourisation of water are 334 kJ 1 and 2491 kJ kg 1, respectively). (log 273 = 2.436, log 373 = 2.572, log 383 = 2.583)
- A7.90 kJ kg 1 K 1
- B2.64 kJ kg 1 K 1
- C8.49 kJ kg 1 K 1
- D9.26 kJ kg 1 K 1
View written solutionFree
Correct answer: D
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Break the process into reversible steps for of substance:
- Ice at water at
- Water at water at
- Water at vapour at
- Vapour at vapour at
Total entropy change:
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Step 1: Melting of ice at
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Step 2: Heating liquid water from to
For heating at constant pressure:
Here , .
Using ,
Therefore,
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Step 3: Vaporisation at
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Step 4: Heating steam from to
Hence,
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Add all contributions
This matches closest with:
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Option check
- A: ❌
- B: ❌
- C: ❌
- D: ✅
Therefore, the correct option is D.
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