The $E^{0}_{Red}$ values for elements $I, II, III,$ and $IV$ are $-3.04 \, V, -1.90 \, V, 0.00 \, V,$ and $1.90 \, V$ respectively. Which element has the maximum reducing power?

For four metals $A, B, C$ and $D$,the standard reduction potentials are $-3.05 \ V, -1.66 \ V, -0.40 \ V$ and $0.80 \ V$ respectively. Which metal exhibits the highest chemical reactivity?

What is denoted by a negative $E^o$ and a positive $E^o$ value in electrochemistry?

Which of the following transformations can be carried out by using $HI$ as a reducing agent,under acidic conditions?
[Given: $I_{2(s)} \rightarrow 2I^- ; E^{\circ} = 0.54 \ V$]
$(i)$ $Cu^+ \rightarrow Cu_{(s)} ; E^{\circ} = 0.52 \ V$
$(ii)$ $Cr^{3+} \rightarrow Cr^{2+} ; E^{\circ} = -0.41 \ V$
$(iii)$ $Fe^{3+} \rightarrow Fe^{2+} ; E^{\circ} = 0.77 \ V$
$(iv)$ $Fe^{2+} \rightarrow Fe_{(s)} ; E^{\circ} = -0.44 \ V$

Standard electrode potential of $SHE$ at $298 \, K$ is ............. $V$.

Assertion : Copper reacts with $HCl$ and liberates hydrogen.
Reason : Hydrogen is present above $Cu$ in the reactivity series.