What is $E_{\text {cell }}$ (in V) of the following cell at $298 \mathrm{~K} ?$

$$ \begin{aligned} & \left(E_{\mathrm{Zn}^{2+} / \mathrm{Zn}}^{\ominus}=-0.76 \mathrm{~V} ; E_{\mathrm{Ni}^{2+} / \mathrm{Ni}}^{\ominus}=-0.25 \mathrm{~V} ; \frac{2.303 R T}{F}=0.06 \mathrm{~V}\right) \\ & 1(s) \mathrm{Zn}^{2+}(0.01 \mathrm{M}) \mathrm{Ni}^{2+}(0.1 \mathrm{M}) \mathrm{Ni}(s \end{aligned} $$

At 300 K , the $E_{\text {cell }}^{\ominus}$ of

$$ A(s)+B^{2+}(a q) \rightleftharpoons A^{2+}(a q)+B(s) $$

is 1.0 V . If $\Delta_r S^\theta$ of this reaction is $100 \mathrm{JK}^{-1}$. What is $\Delta_r H^{\ominus}$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) of this reaction?

$$ \left(\mathrm{F}=96500 \mathrm{C} \mathrm{~mol}^{-1}\right) $$

Consider the cell reaction at 300 K .

$$ A(s)+B^{2+}(a q) \rightleftharpoons A^{2+}(a q)+B(s) $$

Its $E^{\ominus}$ is 1.0 V . The $\Delta_r H^{\ominus}$ of the reaction is $-163 \mathrm{kJmol}^{-1}$.

What is $\Delta_r s^{\ominus}$ (in $\mathrm{JK}^{-1}$ ) of the reaction?

$$ \left(F=96500 \mathrm{C} \mathrm{~mol}^{-1}\right) $$

In which of the following Galvanic cells emf is maximum?

(Given, $E_{\mathrm{Mg}^{2+} \mid \mathrm{Mg}}^{\circ}=-2.36 \mathrm{~V}$

and $E_{\mathrm{Cl}_2 \mid 2 \mathrm{Cl}^{-}}^{\circ}=+136 \mathrm{~V}$ )