Which chemical equation represents the standard reduction potential of zinc?

If the $\Delta G$ of a cell reaction $AgCl + e^- \to Ag + Cl^{-}$ is $-21.20 \ kJ$,the standard e.m.f. of the cell is ............ $V$.

The standard electrode potentials $E^{\circ} (V)$ for $Li^{+} / Li$ and $Na^{+} / Na$ respectively are:

Given that the standard potentials $(E^{\circ})$ of $Cu^{2+}/Cu$ and $Cu^{+}/Cu$ are $0.34 \ V$ and $0.522 \ V$ respectively,the $E^{\circ}$ of $Cu^{2+}/Cu^{+}$ is (in $V$)

The value of $x$ from the given data is

The standard reduction potential at $298 \ K$ for the following half cells are given below :-
$NO_3^{-} + 4H^{+} + 3e^{-} \rightarrow NO_{(g)} + 2H_2O \quad E^0 = 0.97 \ V$

$V^{2+}_{(aq)} + 2e^{-} \rightarrow V_{(s)}$	$E^0 = -1.19 \ V$
$Fe^{3+}_{(aq)} + 3e^{-} \rightarrow Fe_{(s)}$	$E^0 = -0.04 \ V$
$Ag^{+}_{(aq)} + e^{-} \rightarrow Ag_{(s)}$	$E^0 = 0.80 \ V$
$Au^{3+}_{(aq)} + 3e^{-} \rightarrow Au_{(s)}$	$E^0 = 1.40 \ V$

The number of metal$(s)$ which will be oxidized by $NO_3^{-}$ in aqueous solution is $....$.