The cell potential for the unbalanced chemical reaction :

${\mathrm{Hg}}_2^{2+}+{\mathrm{NO}}_3^{-}+{\mathrm{H}}^{+}⟶{\mathrm{Hg}}^{2+}+{\mathrm{HNO}}_2+{\mathrm{H}}_2\mathrm{O};{\mathrm{E}}_{\mathrm{cell} }^{\mathrm{o}}=0.02 \mathrm{V}$

$\left(\frac{2.303\mathrm{RT}}{F}=0.06\right)$

Then choose the correct statement.

The following reaction takes place at $25°\mathrm{C}$.

$\mathrm{Sn} \left(\mathrm{s}\right) + {\mathrm{Pb}}^{2+}\left(\mathrm{aq}\right)\to {\mathrm{Sn}}^{2+}\left(\mathrm{aq}\right) + \mathrm{Pb} \left(\mathrm{s}\right); {\mathrm{E}}_{\mathrm{cell}}^0 =0.01 \mathrm{V}$

If an excess of tin metal is added to $1.0 \mathrm{M} {\mathrm{Pb}}^{2+}$, what is the concentration of ${\mathrm{Pb}}^{2+}$at equilibrium?

Answer correct up to one place of decimal.

Calculate the equilibrium constant for the reaction $2{\mathrm{Fe}}^{3+}+3{\mathrm{I}}^{-}\rightleftharpoons 2{\mathrm{Fe}}^{2+}+{\mathrm{I}}_3^{-}$. The standard reduction potentials in acidic-medium conditions are $0.77$and $0.54 \mathrm{V}$ respectively for ${\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}$ and ${\mathrm{I}}_3^{-}/{\mathrm{I}}^{-}$ couples.

If the answer is of type $\mathrm{y}\times {10}^7$, report the value of $\mathrm{y}$ correct up to the nearest integer.

In the following process of disproportionation,

${\underset{\begin{array}{c}\mathrm{Chlorate}\\ \mathrm{ion}\end{array}}{2{\mathrm{ClO}}_3^{-}}⟶{\mathrm{ClO}}_2^{-}+\underset{\begin{array}{c}\mathrm{Perchlorate}\\ \mathrm{ion}\end{array}}{{\mathrm{ClO}}_4^{-}}}_{{\mathrm{E}}_{\frac{{\mathrm{ClO}}_3^{-}}{{\mathrm{ClO}}_2^{-}}}^{°}=+0.33 \mathrm{V}}^{{\mathrm{E}}_{\frac{{\mathrm{ClO}}_4^{-}}{{\mathrm{ClO}}_3^{-}}}^{°}=+0.36 \mathrm{V}}$

Initial concentration of chlorate ion was $0.1 \mathrm{M}$. The equilibrium concentration of per chlorate ion will be $1.9\times {10}^{-\mathrm{x}}$. Hence $\mathrm{x}$ is $\frac{2.303 \mathrm{RT}}{\mathrm{nF}}=0.06$