Standard potential of electrode reaction $Cu^{2+}_{(aq)} + 2e^{-} \rightarrow Cu_{(s)}$ is $+0.34 \ V$. What is the standard potential of the reaction $2Cu_{(s)} \rightarrow 2Cu^{2+}_{(aq)} + 4e^{-}$?

Given that $E^o_{K^{+}/K} = -2.93 \ V$,$E^o_{Fe^{2+}/Fe} = -0.44 \ V$,$E^o_{Zn^{2+}/Zn} = -0.76 \ V$,and $E^o_{Cu^{2+}/Cu} = 0.34 \ V$. Based on this data,which of the following is the strongest reducing agent?

Among $Mg$,$Cu$,$Fe$,and $Zn$,the metal that does not produce hydrogen gas in reaction with hydrochloric acid is:

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

The standard reduction potential for $Li^{+}/Li$,$Zn^{2+}/Zn$,$H^{+}/H_2$ and $Ag^{+}/Ag$ is $-3.05$,$-0.762$,$0.00$ and $+0.80 \ V$. Which of the following has the highest reducing capacity?

The reducing ability of the metals $K$,$Au$,$Zn$ and $Pb$ follows the order