Chemistry - Thermodynamics - I Question with Solution | TestHub

(P) $\frac{3}{2}{\mathrm{O}}_2\rightleftharpoons {\mathrm{O}}_3$

$\Delta {\mathrm{H}}_{\mathrm{f}}^0>0$ decomposition of ${\mathrm{O}}_2$

$\Delta {\mathrm{U}}_{\mathrm{f}}^0>0$ is exothermic.

$\Delta {\mathrm{H}}_{\mathrm{f}}^0=\Delta {\mathrm{U}}_{\mathrm{f}}^0+\Delta {\mathrm{n}}_{\mathrm{g}}\mathrm{RT}$

or, $\Delta {\mathrm{H}}_{\mathrm{f}}^0-\Delta {\mathrm{U}}_{\mathrm{f}}^0=-0.5\mathrm{RT}<0$

$\Rightarrow \Delta {\mathrm{H}}_{\mathrm{f}}^0<\Delta {\mathrm{U}}_{\mathrm{f}}^0$

$\therefore (\mathrm{P})⟶2,5$

(Q) ${\mathrm{I}}_2(\mathrm{s})\rightleftharpoons {\mathrm{I}}_2(\mathrm{g})$

$$\begin{array}{rlrlr}& \Delta {\mathrm{H}}_{\mathrm{f}}^0>0,\Delta {\mathrm{U}}_{\mathrm{f}}^0>0& & & \end{array}$$

$$\Delta {\mathrm{H}}_{\mathrm{f}}^0=\Delta {\mathrm{U}}_{\mathrm{f}}^0+\mathrm{RT}$$

$$or,\Delta {\mathrm{H}}_{\mathrm{f}}^0-\Delta {\mathrm{U}}_{\mathrm{f}}^0>0\Rightarrow \Delta {\mathrm{H}}_{\mathrm{f}}^0>\Delta {\mathrm{U}}_{\mathrm{f}}^0$$

$$(\mathrm{Q})\to 2,4$$

(R) Sn(white)

$$\begin{array}{rlrl}& \Delta H_f^0=0,\Delta U_f^0=0& \Delta H_f^0-\Delta U_f^0=0& \end{array}$$

$$(R)\to 1$$

(S) ${\mathrm{H}}_2(\mathrm{g})+\frac{1}{2}{\mathrm{O}}_2(\mathrm{g})\rightleftharpoons {\mathrm{H}}_2\mathrm{O}(\mathrm{g})$ $\Delta {\mathrm{H}}_{\mathrm{f}}^0<0,\Delta {\mathrm{U}}_{\mathrm{f}}^0<0$ $\Delta {\mathrm{H}}_{\mathrm{f}}^0=\Delta {\mathrm{U}}_{\mathrm{f}}^0-0.5\mathrm{RT}$

or, $\Delta {\mathrm{H}}_{\mathrm{f}}^0-\Delta {\mathrm{U}}_{\mathrm{f}}^0<0\Rightarrow \Delta {\mathrm{H}}_{\mathrm{f}}^0<\Delta {\mathrm{U}}_{\mathrm{f}}^0$

$(\mathrm{S})\to 3,5$ [0pt]