When a lead storage battery is charged,it acts as:

The $emf$ of the cell reaction is $1.1 \ V$. Calculate the free energy change for the reaction in $kJ$:
$Zn_{(s)} + Cu^{+2}_{(aq)} \longrightarrow Zn^{+2}_{(aq)} + Cu_{(s)}$

The cells which can be recharged are:

During discharging,the change taking place at the cathode in a lead accumulator is:

For the cell $Cu_{(s)} | Cu^{2+}_{(aq)} (1 \ M) || Zn^{2+}_{(aq)} (1 \ M) | Zn_{(s)}$,given $E^{\circ}_{Zn^{2+}/Zn} = -0.76 \ V$ and $E^{\circ}_{Cu^{2+}/Cu} = 0.34 \ V$,the cell reaction is:

Arrange the following metals in the order in which they displace each other from the solution of their salts: $Al$,$Cu$,$Fe$,$Mg$,and $Zn$.