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JEE Main201910 Jan 2019Morning ShiftChemistryThermodynamics (C)Actual

A process has Δ H = 200   J   m o l - 1 and Δ S = 40   J K - 1 m o l - 1 . Out of the values given below choose the minimum temperature above which the process will be spontaneous:

Options

  1. A20 K
  2. B5 K
  3. C12 K
  4. D4 K

Correct answer

B. 5 K

Step-by-step solution

∆ G = ∆ H - T ∆ S ....... (Gibbs Helmholtz Equation) For a reaction to be spontaneous, ∆ G < 0 So, ∆ H - T ∆ S < 0 ∆ H < T ∆ S ∆ H ∆ S < T i.e. Minimum temp. should be &#x21D2; ∆ H ∆ S = 200 40 = 5 K

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