The standard electrode potential $(E^o)$ of $Cu^{2+}/Cu$ is $+0.34 \, V$,while that of $Zn^{2+}/Zn$ is $-0.76 \, V$. Explain the reason for this difference.

Four alkali metals $A$,$B$,$C$ and $D$ have standard electrode potentials of $-3.05 \ V$,$-1.66 \ V$,$-0.40 \ V$ and $0.80 \ V$ respectively. Which one will be the most reactive?

The $E^o$ for the reduction of $NO_3^-$ ion in aqueous solution is $+0.96 \, V$. The $E^o$ values for several metal ions are given below:
$V^{2+}_{(aq)} + 2e^{-} \rightarrow V, \, E^o = -1.19 \, V;$
$Fe^{3+}_{(aq)} + 3e^{-} \rightarrow Fe, \, E^o = -0.04 \, V;$
$Au^{3+}_{(aq)} + 3e^{-} \rightarrow Au, \, E^o = +1.40 \, V;$
$Hg^{2+}_{(aq)} + 2e^{-} \rightarrow Hg, \, E^o = +0.86 \, V$
Which of the following pairs of metals is $NOT$ oxidized by $NO_3^-$ in aqueous solution?

Which metal does not give the following reaction? $M + \text{water} \rightarrow \text{oxide or hydroxide} + H_2$

Given that the standard reduction potentials for $M^{+}/M$ and $N^{+}/N$ electrodes at $298 \ K$ are $0.52 \ V$ and $0.25 \ V$ respectively. Which of the following is correct in respect of the following electrochemical cell?
$M | M^{+} || N^{+} | N$

For $Mg^{2+} + 2e^{-} \rightarrow Mg_{(s)}$,$E^{0} = -2.37 \, V$ and for $Cu^{2+} + 2e^{-} \rightarrow Cu_{(s)}$,$E^{0} = +0.33 \, V$. The $emf$ of the cell $(E^{0}_{Cell})$ is .......... $V$.