$E^{\circ}_{Fe^{2+}/Fe} = -0.441 \ V$ and $E^{\circ}_{Fe^{3+}/Fe^{2+}} = 0.771 \ V$,the standard $EMF$ of the reaction $Fe + 2Fe^{3+} \rightarrow 3Fe^{2+}$ will be $.......... \ V$.

Consult the table of standard electrode potentials and suggest three substances that can oxidise ferrous ions under suitable conditions.

Based on the given standard electrode potentials,identify the metal that can be displaced from its salt solution by all other metals listed.
$E^o Zn^{2+}/Zn = -0.76 \ V, E^o Cu^{2+}/Cu = +0.34 \ V$
$E^o Ag^+/Ag = +0.80 \ V, E^o Co^{2+}/Co = -0.28 \ V$

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

$MnO_4^- (aq) + 8H^+ (aq) + 5e^- \to Mn^{2+} (aq) + 4H_2O (l)$; $E_1^o = 1.51 \ V$
$MnO_2 (s) + 4H^+ (aq) + 2e^- \to Mn^{2+} (aq) + 2H_2O (l)$; $E_2^o = 1.21 \ V$
$MnO_4^- (aq) + 4H^+ (aq) + 3e^- \to MnO_2 (s) + 2H_2O (l)$; $E_3^o = ?$
Value of $E_3^o$ will be ............ $V$

Bubbles of gas $z$ are evolved from a solution containing $x$ and $y$. If the order of reduction potential is $x > y > z$,then: