What is a nickel-cadmium cell? State its one merit and one demerit over lead storage cell. Write the overall reaction that occurs during discharging of this cell.

Calculate the standard cell potential at ${25}^{°}\mathrm{C}$ for the electrochemical cells: $\mathrm{Zn}\overline{){\mathrm{Zn}}^{2+}\parallel {\mathrm{Cu}}^{2+}\overline{)\mathrm{Cu}}}$, where the reference half cell is $\mathrm{SHE}$.

Calculate the standard cell potential at ${25}^{°}\mathrm{C}$ for the electrochemical cells. $\mathrm{Zn}\overline{){\mathrm{Zn}}^{2+}}\parallel {\mathrm{Cu}}^{2+}\overline{)\mathrm{Cu}}$, where the reference half cell is $\mathrm{Ag}/\mathrm{AgCl}$ electrode.

Calculate the standard electrode potential of ${\mathrm{Ni}}^{2+}\overline{)\mathrm{Ni}}$ electrode if emf of the cell, $\mathrm{Ni}\left(\mathrm{s}\right) \overline{) {\mathrm{Ni}}^{2+}(0.01 \mathrm{M})\parallel {\mathrm{Cu}}^{2+}(0.1 \mathrm{M}) \overline{)\mathrm{Cu}\left(\mathrm{s}\right)}}$ is $0.059 \mathrm{V}$ [Given, ${{\mathrm{E}}^{°}}_{\left({\mathrm{Cu}}^{2+}\overline{)\mathrm{Cu}}\right)}=+0.34 \mathrm{V}$].

A strip of nickel metal is placed in a $1$ molar solution of $\mathrm{Ni}({\mathrm{NO}}_3{)}_2$ and a strip of silver metal is placed in a one molar solution of ${\mathrm{AgNO}}_3$. An electrochemical cell is created when the two solutions are connected by a salt bridge and the two strips are connected by wires to a voltmeter. Write the balanced equations for the overall reaction occurring in the cell.