Consider the following cell reaction

$$ 2 \mathrm{Fe}^{3+}(a q)+2 \mathrm{I}^{-}(a q) \rightleftharpoons 2 \mathrm{Fe}^{2+}(a q)+\mathrm{I}_2(s) $$

At 298 K , the cell emf is 0.237 V . The equilibrium constant for the reaction is $10^x$. The value of $x$ is $\left(F=96500 \mathrm{C} \mathrm{mol}^{-1} ; R=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)$.

When the lead storage battery is in use (during discharge) the reaction that occurs at the anode is

$$ \text { Match the following } $$

$$ \begin{array}{cccc} \hline & \begin{array}{c} \text { List-I } \\ \text { (Transition metal, M) } \end{array} & & \begin{array}{c} \text { List-II } \\ \left(E_{M^{2+} / M}^{\ominus}\right) \end{array} \\ \hline \text { (A) } & \mathrm{Ni} & \text { (I) } & -1.18 \\ \hline \text { (B) } & \mathrm{Mn} & \text { (II) } & -0.91 \\ \hline \text { (C) } & \mathrm{Fe} & \text { (III) } & -0.25 \\ \hline \text { (D) } & \mathrm{Cr} & \text { (IV) } & -0.44 \\ \hline \end{array} $$

The correct answer is

At 298 K , the following reaction takes place for a cell at the hydrogen electrode

$$ \mathrm{H}^{+}(a q)+e^{-} \longrightarrow \frac{1}{2} \mathrm{H}_2 \text { (1 bar) } $$

The solution pH is 10.0 . What is the hydrogen electrode potential in volts?

$$ \left(\frac{2303 R T}{F}=0.06 \mathrm{~V}\right) $$