Identify the correct statements from the following. I. $\Delta_r G$ is zero for $A \rightleftharpoons B$ reaction. II. The entropy of pure crystalline solids approaches. zero as the temperature approaches absolute zero. III. $\Delta U$ of a reaction can be determined using bomb calorimeter.

Observe the following reactions.

$$ \begin{array}{ll} A B(g)+25 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow\left(25 \mathrm{H}_2 \mathrm{O}\right) A B ; & \Delta H=x \mathrm{~kJ} \mathrm{~mol}^{-1} \\ A B(g)+50 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow\left(50 \mathrm{H}_2 \mathrm{O}\right) A B ; & \Delta H=y \mathrm{~kJ} \mathrm{~mol}^{-1} \end{array} $$

The equation that represents 'coal gasification' is

The standard free energy change $\left(\Delta G^{\circ}\right)$ for the following reaction (in kJ ) at $25^{\circ} \mathrm{C}$ is $$ 3 \mathrm{Ca}(s)+2 \mathrm{Au}^{3+}(a q, 1 M) \longrightarrow 3 \mathrm{Ca}^{2+}(a q, 1 M)+2 \mathrm{Au}(s) $$