If the standard reduction potentials of four electrodes $A$, $B$, $C$, and $D$ are $+2.5 \text{ V}$, $+3.0 \text{ V}$, $-2.0 \text{ V}$, and $-1.5 \text{ V}$ respectively, in which of the following cases is the standard $emf$ of the cell maximum?

Given $E_{Cu^{2+}/Cu^{+}}^o = 0.15 \, V$,$E_{Cu^{2+}/Cu}^o = 0.34 \, V$. The standard electrode potential for the half-cell $Cu^{+}/Cu$ is ............. $V$.

The standard reduction potentials at $25^o C$ are given below. Which is the strongest reducing agent?
$Zn^{2+}_{(aq)} + 2e^{-} \rightleftharpoons Zn_{(s)}$,$E^o_{RP} = -0.762 \, V$
$Cr^{3+}_{(aq)} + 3e^{-} \rightleftharpoons Cr_{(s)}$,$E^o_{RP} = -0.740 \, V$
$2H^{+}_{(aq)} + 2e^{-} \rightleftharpoons H_{2(g)}$,$E^o_{RP} = 0.00 \, V$
$Fe^{3+}_{(aq)} + e^{-} \rightleftharpoons Fe^{2+}_{(aq)}$,$E^o_{RP} = 0.77 \, V$

Which of the following metals will not release $H_{2(g)}$ upon reaction with an acid?

Can $E_{cell}^o$ or $\Delta_r G^o$ for a cell reaction ever be equal to zero?

If the $emf$ of the cell $Cu(s) | Cu^{2+}(1 \text{ M}) || Ag^+(1 \text{ M}) | Ag(s)$ is $0.463 \text{ V}$ at $25^{\circ} \text{C}$ and the standard electrode potential of the $Cu$ electrode is $0.337 \text{ V}$, find the standard electrode potential of the $Ag$ electrode. (in $\text{ V}$)