Which of the following conditions correctly predict the thermodynamic spontaneity of a reaction at c — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

The driving force for spontaneity is $\Delta G < 0$. (A) An exothermic reaction ($\Delta H < 0$) with an increase in entropy ($\Delta S > 0$) guarantees a negative $\Delta G$ regardless of $T$. (B) An endothermic reaction ($\Delta H > 0$) with a decrease in entropy ($\Delta S < 0$) yields $\Delta G > 0$ always. (C) An endothermic reaction with increasing entropy relies on the $-T\Delta S$ term to overcome the positive $\Delta H$; thus it requires high temperatures ($T > \Delta H / \Delta S$). Option D is incorrect because exothermic reactions with decreasing entropy are spontaneous strictly at *low* temperatures ($T < \Delta H / \Delta S$).