The standard reduction potential for $Fe^{2+}/Fe$ and $Sn^{2+}/Sn$ electrodes are $-0.44 \ V$ and $-0.14 \ V$ respectively. For the cell reaction,$Fe^{2+} + Sn \longrightarrow Fe + Sn^{2+}$,the standard emf is:

Given $E_{Cu^{2+}/Cu}^{\circ} = 0.34 \ V$ and $E_{Cu^{2+}/Cu^{+}}^{\circ} = 0.15 \ V$. Calculate the standard electrode potential $E_{Cu^{+}/Cu}^{\circ}$ in $V$.

Given $E_{Fe^{+3}/Fe}^{\circ} = -0.036 \ V$ and $E_{Fe^{+2}/Fe}^{\circ} = -0.439 \ V$,calculate the standard electrode potential for the reaction: $Fe^{+3}_{(aq)} + e^{-} \rightarrow Fe^{+2}_{(aq)}$ (in $V$)

Standard electrode potential of $Ag^{+}/Ag$ and $Cu^{2+}/Cu$ is $+0.80 \ V$ and $+0.34 \ V$ respectively. These electrodes are joined together by a salt bridge. If:

For the given cell reaction $Fe^{2+}_{(aq)} + Ag^{+}_{(aq)} \rightarrow Fe^{3+}_{(aq)} + Ag_{(s)}$,the standard cell potential is:
Given:
$Ag^{+} + e^{-} \rightarrow Ag \quad E^0 = x \ V$
$Fe^{2+} + 2e^{-} \rightarrow Fe \quad E^0 = y \ V$
$Fe^{3+} + 3e^{-} \rightarrow Fe \quad E^0 = z \ V$

For the reaction $Cr_2O_7^{2-} + I^- \to I_2 + Cr^{3+}$,if $E_{cell}^o = 0.79 \ V$ and $E_{Cr_2O_7^{2-}}^o = 1.33 \ V$,then $E_{I_2}^o = $ ............. $V$.