Easy MCQ +4 / -1 PYQ · JEE Mains 2025

Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boiling point of water. Choose the correct option.

  1. A Both $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ are (-ve)
  2. B $\Delta \mathrm{H}$ is $(+\mathrm{ve})$ but $\Delta \mathrm{S}$ is (-ve)
  3. C $\Delta \mathrm{H}$ is $(-\mathrm{ve})$ but $\Delta \mathrm{S}$ is (+ve)
  4. D Both $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ are (+ve) Correct answer

Solution

<p>Reaction is spontaneous at relatively high temperature and non-spontaneous at low temperature $\Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T} \Delta \mathrm{S}$ It is only possible when $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ both are positive.</p> <p>Option (1)</p>

About this question

Subject: Chemistry · Chapter: Thermodynamics · Topic: Zeroth and First Law

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