In the button cells widely used in watches and other devices,the following reaction takes place:
$Zn_{(s)} + Ag_2O_{(s)} + H_2O_{(l)} \rightarrow Zn^{2+}_{(aq)} + 2Ag_{(s)} + 2OH^{-}_{(aq)}$
Determine $\Delta_r G^\Theta$ and $E^\Theta$ for the reaction.

Give the symbolic representation of the galvanic cell obtained by using the following standard reduction potentials at $298 \ K$ and calculate its standard cell potential $(E^o_{cell})$.
$(i)$ $E^o_{Ag^{+}|Ag} = 0.80 \ V$
$(ii)$ $E^o_{Zn^{2+}|Zn} = -0.76 \ V$

$A$ button cell used in watches functions as follows:
$Zn_{(s)} + Ag_2O_{(s)} + H_2O_{(l)} \rightarrow 2Ag_{(s)} + Zn^{2+}_{(aq)} + 2OH^{-}_{(aq)}$
If the half-cell potentials are:
$Zn^{2+}_{(aq)} + 2e^- \rightarrow Zn_{(s)} \,;\, E^o = -0.76 \, V$
$Ag_2O_{(s)} + H_2O_{(l)} + 2e^- \rightarrow 2Ag_{(s)} + 2OH^{-}_{(aq)} \,;\, E^o = 0.34 \, V$
The cell potential will be $..........$ $V.$

An electrochemical cell is constructed using half-cells in the direction of spontaneous change: $Fe(OH)_{2}(s) + 2e^{-} \rightarrow Fe(s) + 2OH^{-}(aq)$ $(E^{0} = -0.88 \text{ V})$ and $AgBr(s) + e^{-} \rightarrow Ag(s) + Br^{-}(aq)$ $(E^{0} = +0.07 \text{ V})$. Which of the following options is correct?

Observe the following statements about a dry cell:
$I$. It is a primary battery.
$II$. Zinc vessel acts as cathode.
$III$. $A$ paste of moist $NH_4Cl$,$MnO_2$ and $ZnCl_2$ is present between two electrodes.
$IV$. The potential of this cell is $1.5 \ V$.
The correct statements are:

$A$ solution containing $1 \ mol \ L^{-1}$ of each $Cu(NO_3)_2, AgNO_3, Hg_2(NO_3)_2$ and $Mg(NO_3)_2$ is being electrolysed using inert electrodes. The standard reduction potentials are $E^0_{Ag^{+}/Ag} = +0.80 \ V, E^0_{Hg_2^{2+}/Hg} = +0.79 \ V, E^0_{Cu^{2+}/Cu} = +0.34 \ V, E^0_{Mg^{2+}/Mg} = -2.37 \ V$. With increasing voltage,the sequence of deposition of metals on the cathode will be: