$A$ battery is made from $Cr$ and $Na_2Cr_2O_7$. When this battery discharges according to the reaction $Na_2Cr_2O_7 + Cr + H^{+} \rightarrow Cr^{3+} + H_2O + Na^{+}$,the chemical equation is unbalanced. If $1 \ F$ (Faraday) of electricity is passed during the charging of the battery,what is the number of moles of $Cr^{3+}$ removed from the solution (in $/3$)?

Which of the following statements is not correct?

For a spontaneous reaction,determine the values of $\Delta G^o$,equilibrium constant $K$,and $E^o_{cell}$ respectively.

At $25^\circ \text{C}$,given the following data: $Ag_{(s)} + I^-_{(aq)} \rightarrow AgI_{(s)} + e^-$,$E^o = 0.152 \ V$; $Ag_{(s)} \rightarrow Ag^+_{(aq)} + e^-$,$E^o = -0.800 \ V$. What is the value of $\log \ K_{sp}$ for $AgI$? (where $K_{sp} = \text{solubility product}$)

For a lead storage battery, pick the correct statements:
$A.$ During charging of the battery, $PbSO_4$ on the anode is converted into $Pb$.
$B.$ During charging of the battery, $PbSO_4$ on the cathode is converted into $PbO_2$.
$C.$ The lead storage battery consists of a grid of lead packed with $PbO_2$ as the cathode.
$D.$ The lead storage battery has a $\sim 38\%$ solution of sulphuric acid as an electrolyte.
Choose the correct answer from the options given below:

Copper from copper sulphate solution can be displaced by .............. The standard reduction potentials of some electrodes are given below:
$E^o (Fe^{2+}, Fe) = -0.44 \ V$
$E^o (Zn^{2+}, Zn) = -0.76 \ V$
$E^o (Cu^{2+}, Cu) = +0.34 \ V$
$E^o (Cr^{2+}, Cr) = -0.74 \ V$
$E^o (H^{+}, 1/2H_2) = 0.00 \ V$