The standard reduction electrode potentials of four elements are:
$A = -0.250 \ V$,$B = -0.136 \ V$,$C = -0.126 \ V$,$D = -0.402 \ V$
The element that displaces $A$ from its compounds is:

Which of the following has the least tendency to liberate $H_2$ from mineral acids?

The values of $E^0$ for metals $A$,$B$,and $C$ are $0.34 \ V$,$-0.80 \ V$,and $-0.46 \ V$ respectively. State the correct order for their ability to act as reducing agents.

$I_2 + 2e^{-} \to 2I^{-}$; $E^{o} = 0.54 \ V$
$Cl_2 + 2e^{-} \to 2Cl^{-}$; $E^{o} = 1.36 \ V$
$Mn^{3+} + e^{-} \to Mn^{2+}$; $E^{o} = 1.50 \ V$
$Fe^{3+} + e^{-} \to Fe^{2+}$; $E^{o} = 0.77 \ V$
Which of the following is a correct statement?

Given standard electrode potentials:
$Fe^{2+} + 2e^- \to Fe; E^o = -0.440 \ V$
$Fe^{3+} + 3e^- \to Fe; E^o = -0.036 \ V$
The standard electrode potential $(E^o)$ for $Fe^{3+} + e^- \to Fe^{2+}$ is .............. $V$.

The $E^o$ for half cells $Fe/Fe^{2+}$ and $Cu/Cu^{2+}$ are $-0.44 \, V$ and $+0.32 \, V$ respectively. Then