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MHT CET202521 Apr 2025Morning ShiftChemistryThermodynamics (C)Actual

Which of the following set of thermodynamic conditions is true for the reaction to be spontaneous at high temperature?

Options

  1. AH < 0 and S < 0
  2. BH>0 and S>0
  3. CH 0
  4. DH>0 and S < 0

Correct answer

B. H>0 and S>0

Step-by-step solution

The spontaneity of a reaction is determined by the sign of its Gibbs free energy change, G = H - T S . A negative G Option A ( H yields G = negative - T( negative ) . The reaction is spontaneous only at low temperatures when | H| > |T S| . Option B ( H > 0 , S > 0 ) gives G = positive - T( positive ) . This results in spontaneity at high temperatures where T S > H . Option C ( H 0 ) produces G = negative - T( positive ) , which is always negative, making the reaction spontaneous at all temperatures. Option D ( H >

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