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MHT CET202013 Oct 2020Morning ShiftChemistryThermodynamics (C)Actual

For a reaction H =-30 ~kJ and S =-45 ~J ~K ⁻¹ , at what temperature reaction changes from spontaneous to non spontaneous?

Options

  1. A777 0 ~K
  2. B675 0 ~K
  3. C666 6 ~K
  4. D375 0 ~K

Correct answer

C. 666 6 ~K

Step-by-step solution

array l H =-30 ~kJ , S =-45 ~J ~K ⁻¹=-0.045 ~kJ ~K ⁻¹ T = H S = -30 ~kJ -0.045 ~kJ ~K ⁻¹ =666.67 ~K array Since H and S are both negative, the reaction is spontaneous at low temperature and nonspontaneous above 666.67 ~K .

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