When a lead storage battery is charged,what happens?

In which of the following solutions will a blue color appear after some time when a piece of $Cu$ metal is added?

Which of the following reactions occurs at the cathode during the charging of a lead storage battery?

The equilibrium constant for the reaction $Zn_{(s)} + Sn^{2+}_{(aq)} \rightleftharpoons Zn^{2+}_{(aq)} + Sn_{(s)}$ is $1 \times 10^{20}$ at $298 \ K$. The magnitude of standard electrode potential of $Sn/Sn^{2+}$ if $E_{Zn^{2+}/Zn}^0 = -0.76 \ V$ is $............ \times 10^{-2} \ V$. (Nearest integer)
Given : $\frac{2.303 \ RT}{F} = 0.059 \ V$

Which of the following is $NOT$ true about a voltaic cell?

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.