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NEET2020ChemistryThermodynamics (C)Actual

If for a certain reaction Δ r H is 30   kJmol - 1 at 450 K , the value of Δ r S (in JK - 1 mol - 1 ) for which the same reaction will be spontaneous at the same temperature is

Options

  1. A70
  2. B- 33
  3. C33
  4. D- 70

Correct answer

A. 70

Step-by-step solution

ΔG = ΔH - TΔS For spontaneous, Δ G < 0 Δ H - T Δ S < O Δ S > Δ H T Δ S > 30 × 10 3 Jmol - 1 450 K Δ S > 66 . 6   Jmol - 1 K - 1 (Check by options) So, option (1) , i.e. (70 ~J mol ⁻¹ ~K ⁻¹ ) satisfies it.

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