Match Column I with Column II — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

(A) Freezing is always exothermic ($\Delta H < 0$). $\Delta V$ can be positive (water) or negative (most solids), leading to P or S. (B) $\Delta S < 0$; thus $\Delta G$ can be positive or negative if $\Delta H < 0$ (depending on T), and must be positive if $\Delta H > 0$. This maps to P, R, S. (C) $\Delta H = E_{af} - E_{ab} = +10$ (+ve). $\Delta n_g = 1 \implies \Delta S > 0$. At high T, $\Delta G < 0$ (-ve), giving Q. (D) $\Delta S \approx 0$; at very low T, $T\Delta S \approx 0 \implies \Delta G \approx \Delta H$. Both share the same sign (R, S).