The calomel electrode used as a reference electrode contains which of the following substances?

The standard cell potential $(E_{\text{cell}}^{\ominus})$ of a fuel cell based on the oxidation of methanol in air that has been used to power television relay station is measured as $1.21 \ V$. The standard half-cell reduction potential for $O_2$ $(E_{O_2 / H_2 O}^0)$ is $1.229 \ V$. Choose the correct statement:

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

Which of the following is not used to construct a salt bridge?

Match List-$I$ with List-$II$.

$LIST$-$I$ (Cell)	$LIST$-$II$ (Use/Property/Reaction)
$A$. Leclanche cell	$I$. Converts energy of combustion into electrical energy
$B$. Ni-Cd cell	$II$. Does not involve any ion in solution and is used in hearing aids
$C$. Fuel cell	$III$. Rechargeable
$D$. Mercury cell	$IV$. Reaction at anode $Zn \rightarrow Zn^{2+} + 2e^-$

Choose the correct answer from the options given below:

$A$ lead storage battery is discharged. During the charging of this battery,the reaction that occurs at the anode is: