Consider the following data for the reaction

$$ X_2(g)+Y_2(g) \rightleftharpoons 2 X Y(g) $$

at $600 \mathrm{~K}^{\circ}$. The $\Delta_{\mathrm{r}} \mathrm{G}^{\ominus}$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) for the reaction is :

$$ \begin{array}{|c|c|c|} \hline \text { Compound } & \Delta_f \mathrm{H}_{600 \mathrm{~K}}^{\ominus}\left(\mathrm{kJ} \mathrm{~mol}^{-1}\right) & \mathrm{S}^{\ominus}{ }_{600 \mathrm{~K}}\left(\mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right) \\ \hline \mathrm{XY}(\mathrm{~g}) & 42 & 200 \\ \hline \mathrm{X}_2(\mathrm{~g}) & 8 & 140 \\ \hline \mathrm{Y}_2(\mathrm{~g}) & 80 & 250 \\ \hline \end{array} $$

The correct order of molar heat capacities measured at 298 K and 1 bar is :

The reaction $\mathrm{A}(\mathrm{g}) \rightleftharpoons \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$ was initiated with the amount ' a ' of $\mathrm{A}(\mathrm{g})$. At equilibrium it is found that the amount of $\mathrm{A}(\mathrm{g})$ remaining is ( $\mathrm{a}-x$ ) at a total pressure of p .

The equilibrium constant Kp of the reaction can be calculated from the expression :

One half cell in a voltaic cell is constructed by dipping silver rod in $\mathrm{AgNO}_3$ solution of unknown concentration, other half cell is Zn rod dipped in 1 molar solution of $\mathrm{ZnSO}_4$.

A voltage of 1.60 V is measured at 298 K for this cell. What is the concentration of $\mathrm{Ag}^{+}$ions used in terms of $\log x\left(x=\left[\mathrm{Ag}^{+}\right]\right)$?

$$ \mathrm{E}_{\mathrm{Zn}^{2+} / \mathrm{Zn}}^{\ominus}=-0.76 \mathrm{~V}, \quad \mathrm{E}_{\mathrm{Ag}^{+} / \mathrm{Ag}}^{\ominus}=+0.80 \mathrm{~V}, \frac{2.303 \mathrm{RT}}{\mathrm{~F}}=0.059 \mathrm{~V} $$