The salt that can be used in the salt bridge of an electrochemical cell is:

In an alkaline energy cell the overall cell reaction is as follows:

$\mathrm{Zn}\left(\mathrm{s}\right)+2{\mathrm{MnO}}_2\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\to \mathrm{Zn}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right)+2\mathrm{MnO}\left(\mathrm{OH}\right)$

Which of the following reactions is taking place at the cathode?

Nickel metal is added to a solution containing $1.0 \mathrm{M} {\mathrm{Pb}}^{2+} \left(\mathrm{aq}\right)$ and $1.0 \mathrm{M} {\mathrm{Cd}}^{2+}\left(\mathrm{aq}\right)$. Use the standard reduction potential to determine which of the following reaction (s) will occur.

Reaction $1$: ${\mathrm{Ni}}_{\left(\mathrm{s}\right)}+{\mathrm{Pb}}^{2+}\left(\mathrm{aq}\right)\to {\mathrm{Pb}}_{\left(\mathrm{s}\right)}+{\mathrm{Ni}}^{2+}\left(\mathrm{aq}\right)$

Reaction $2$: ${\mathrm{Ni}}_{\left(\mathrm{s}\right)}+{\mathrm{Cd}}^{2+}\left(\mathrm{aq}\right){\mathrm{Cd}}_{\left(\mathrm{s}\right)}+{\mathrm{Ni}}^{2+}\left(\mathrm{aq}\right)$

Reactions: ${\mathrm{Pb}}^{2+}\left(\mathrm{aq}\right)+2\mathrm{e}={\mathrm{Pb}}_{\left(\mathrm{s}\right)} \mathrm{E}°=-0.13 \mathrm{V}$
${\mathrm{Ni}}^{2+}\left(\mathrm{aq}\right)+2\mathrm{e}={\mathrm{Ni}}_{\left(\mathrm{s}\right)} \mathrm{E}°=-0.23 \mathrm{V}$

${\mathrm{Cd}}^{2+}\left(\mathrm{aq}\right)+2\mathrm{e}={\mathrm{Cd}}_{\left(\mathrm{s}\right)} \mathrm{E}°=-0.40 \mathrm{V}$