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COMEDK202510 May 2025Evening ShiftChemistryThermodynamics (C)Actual

For a hypothetical chemical reaction A ₂+3 ~B ₂+ Heat ---- 2 AB ₃ , which one of the following combinations of state variables would support the spontaneity of the reaction at a particular temperature?

Options

  1. AH 0, G >0
  2. BH >0, ~S 0
  3. CH >0, ~S <0, G <0
  4. DH >0, ~S >0, G <0

Correct answer

D. H >0, ~S >0, G <0

Step-by-step solution

The given reaction is A ₂ + 3 B ₂ + Heat 2 AB ₃ . Since the reaction absorbs heat, it is endothermic, which implies H > 0 . The spontaneity of a reaction is determined by the Gibbs free energy change, G = H - T S . A reaction is spontaneous if G For an endothermic reaction ( H > 0 ) to be spontaneous ( G 0 . Comparing this with the given options, the combination H > 0 , S > 0 , and G Answer: H >0, ~S >0, G <0

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