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WBJEE · Chemistry · Thermodynamics (C)

The values of \(\Delta H\) and \(\Delta S\) of a certain reaction are \(-400 \mathrm{k} \mathrm{J} \mathrm{mol}^{-1}\) and \(-20 \mathrm{kJ} \mathrm{mol}^{-1} \mathrm{K}^{-1}\) respectively. The temperature below which the reaction is spontaneous, is

  1. A \(100 \mathrm{K}\)
  2. B \(20^{\circ} \mathrm{C}\)
  3. C \(20 \mathrm{K}\)
  4. D \(120^{\circ} \mathrm{C}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(20 \mathrm{K}\)

Step-by-step Solution

Detailed explanation

Given, \(\quad \Delta H=-400 \mathrm{kJ} \mathrm{mol}^{-1}\) \[ \Delta S=-20 \mathrm{kJ} \mathrm{mol}^{-1} \mathrm{K}^{-1} \] Gibbs Helmholtz equation is \[ \Delta G=\Delta H-T \Delta S \] For a reaction to be spontaneous, \(\Delta G\) must be…