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Question 800012
JEE Chemistry · Hard

Chemical Thermodynamics and Thermochemistry: JEE Advanced MCQ

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JEE AdvancedHardQuestion 800012

Question

For a reaction, ΔH = −20 kJ and ΔS = −100 J/K. Above what temperature does the reaction become non-spontaneous?
  1. A
    200 K
    Correct
  2. B
    100 K
  3. C
    300 K
  4. D
    400 K

Correct answer

200 K

Explanation

ΔG = ΔH − TΔS = −20000 − T(−100) = −20000 + 100T. Non-spontaneous when ΔG > 0: −20000 + 100T > 0 → T > 200 K. Above 200 K, ΔG > 0, so non-spontaneous.

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