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AP EAMCET202317 May 2023Morning ShiftChemistryThermodynamics (C)Actual

If the enthalpy and entropy change for a reaction at 298 ~K are -145 ~kJ ~mol ⁻¹ and -650 ~J ~K ⁻¹ ~mol ⁻¹ respectively, which one of the following statements is correct?

Options

  1. AG =-50 ~kJ ~mol ⁻¹ , the reaction is spontaneous
  2. BG =-48.7 ~kJ ~mol ⁻¹ , the reaction is non-spontaneous
  3. CG =+50 ~kJ ~mol ⁻¹ , the reaction is spontaneous
  4. DG =48.7 ~kJ ~mol ⁻¹ , the reaction is non-spontaneous

Correct answer

D. G =48.7 ~kJ ~mol ⁻¹ , the reaction is non-spontaneous

Step-by-step solution

G = H - T S We have, H =-145 ~kJ ~mol ⁻¹ and S =-650 ~J ~K ⁻¹ ~mol ⁻¹ G = (-145 ~kJ ~mol ⁻¹ )-298 (-650 10⁻³ ~kJ . . mol ⁻¹ k ⁻¹ )=+48.7 ~kJ ~mol ⁻¹ and the reaction is nonSpontaneous.

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