Suppose that an alkaline dry cell was manufactured using cadmium metal rather than $Zn$. What effect would this have on the standard emf of the cell? The standard reduction potential $E^o_{Cd^{2+}/Cd} = -0.40 \ V$ while $E^o_{Zn^{2+}/Zn} = -0.76 \ V$.

When a lead storage battery is charged,what happens?

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

Select the incorrect option,when a lead storage battery is discharged $-$

What is the value of $n$ in the Daniell cell? Why?

Write the reactions for the following:
$1.$ Oxidation and reduction reactions of a lead storage cell.
$2.$ Cell reaction of a $Ni-Cd$ cell.
$3.$ Anode,cathode,and overall reaction of a mercury cell.