Which of the following reactions exhibits the minimum standard reduction potential?

Standard electrode potential for $Sn^{4+}/Sn^{2+}$ couple is $+0.15 \ V$ and that for the $Cr^{3+}/Cr$ couple is $-0.74 \ V.$ These two couples in their standard state are connected to make a cell. The cell potential will be ........ $V$

What will happen when a silver ring is placed in an acidic solution?

If standard reduction potentials $(E^0)$ of $(Al^{+3}(aq)|Al(s))$, $(Fe^{+2}(aq)|Fe(s))$, $(Cu^{+2}(aq)|Cu(s))$ and $(Ag^{+1}(aq)|Ag(s))$ are $-1.66 \text{ V}$, $-0.44 \text{ V}$, $+0.34 \text{ V}$ and $+0.79 \text{ V}$ respectively, which of the following reactions is non-spontaneous?

Determine true $(T)$ and false $(F)$ for the following statements:
$(i)$ Always $E_{cell}^o = E_{cell}$
$(ii)$ In standard conditions,$E_{cell}^o = E_{cell}$
$(iii)$ $E_{cell}^o = E_{cell}$ is reached when the cell attains equilibrium.
$(iv)$ $E_{cell}^o = -\frac{\Delta_r G^o}{nF}$

Given the following standard electrode potentials:
$Cu^{+2} + 2e^{-} \to Cu$,$E^{o} = X_{1}$
$Cu^{+} + e^{-} \to Cu$,$E^{o} = X_{2}$
Calculate the standard electrode potential $E^{o}$ for the reaction: $Cu^{+2} + e^{-} \to Cu^{+}$