The following reaction occurs in a button cell:
$(i)$ $Ag_{2}O + H_{2}O + 2e^{-} \rightarrow 2Ag + 2OH^{-}$
$(ii)$ $Zn \rightarrow Zn^{2+} + 2e^{-}$
Calculate the standard Gibbs free energy change $\Delta G^{o}$ for the overall cell reaction.
$[E^{o}_{Zn^{2+}\mid Zn} = -0.76 \ V, E^{o}_{Ag_{2}O\mid Ag} = 0.34 \ V]$

The reaction $Zn_{(s)} + 2AgCl_{(s)} \to Zn^{2+}_{(aq)} + 2Ag_{(s)} + 2Cl^{-}_{(aq)}$ will take place in which of the following electrochemical cells?

$Ag/AgCl_{(s)}/KCl$ electrode is

Write the chemistry of recharging the lead storage battery,highlighting all the materials that are involved during recharging.

The standard reduction potential data at $25^{\circ} C$ is given below.
$E^{\circ}(Fe^{3+}, Fe^{2+}) = +0.77 \ V$
$E^{\circ}(Fe^{2+}, Fe) = -0.44 \ V$
$E^{\circ}(Cu^{2+}, Cu) = +0.34 \ V$
$E^{\circ}(Cu^{+}, Cu) = +0.52 \ V$
$E^{\circ}(O_{2(g)} + 4H^{+} + 4e^{-} \rightarrow 2H_{2}O) = +1.23 \ V$
$E^{\circ}(O_{2(g)} + 2H_{2}O + 4e^{-} \rightarrow 4OH^{-}) = +0.40 \ V$
$E^{\circ}(Cr^{3+}, Cr) = -0.74 \ V$
$E^{\circ}(Cr^{2+}, Cr) = -0.91 \ V$
Match $E^{\circ}$ of the redox pair in List-$I$ with the values given in List-$II$ and select the correct answer using the code given below the lists:

List-$I$	List-$II$
$P. \ E^{\circ}(Fe^{3+}, Fe)$	$1. \ -0.18 \ V$
$Q. \ E^{\circ}(4H_{2}O \rightleftharpoons 4H^{+} + 4OH^{-})$	$2. \ -0.4 \ V$
$R. \ E^{\circ}(Cu^{2+} + Cu \rightarrow 2Cu^{+})$	$3. \ -0.04 \ V$
$S. \ E^{\circ}(Cr^{3+}, Cr^{2+})$	$4. \ -0.83 \ V$

Codes: $P \quad Q \quad R \quad S$

Which of the following changes takes place at the positive electrode during the recharging of a lead accumulator?