Which of the following is incorrect in a galvanic cell?

Standard electrode potentials of $Zn$ and $Fe$ are known to be $(i) -0.76 \ V$ and $(ii) -0.44 \ V$ respectively. How does this explain that galvanization prevents rusting of iron while zinc slowly dissolves away?

Explain: Electrochemistry is a wide and interdisciplinary subject.

$A$ depolarizer used in dry cell batteries is

The standard reduction potentials at $298 \ K$ for the following half-cells are given below:
$Cr_2O_7^{2-} + 14H^+ + 6e^- \rightarrow 2Cr^{3+} + 7H_2O$,$E^{\circ} = 1.33 \ V$
$Fe^{3+} + 3e^- \rightarrow Fe$,$E^{\circ} = -0.04 \ V$
$Ni^{2+} + 2e^- \rightarrow Ni$,$E^{\circ} = -0.25 \ V$
$Ag^+ + e^- \rightarrow Ag$,$E^{\circ} = 0.80 \ V$
$Au^{3+} + 3e^- \rightarrow Au$,$E^{\circ} = 1.40 \ V$
Consider the given electrochemical reactions. The number of metal$(s)$ which will be oxidized by $Cr_2O_7^{2-}$ in aqueous solution is $.....$

Efficiency of a cell with cell reaction under standard conditions,$A_{(s)} + B^{+} \to A^{+} + B_{(s)}$; $\Delta H^o = -300 \ kJ$ is $70\%$. The standard electrode potential of the cell is :- .................... $V$