Given that $E^o_{Fe^{2+}/Fe} = -0.44 \ V$,$E^o_{Cu^{2+}/Cu} = 0.34 \ V$,and $E^o_{Ag^+/Ag} = 0.80 \ V$. Which of the following statements is correct?

Which of the following statements is wrong?

Solutions $A$,$B$,and $C$ of the same strong electrolyte offered resistances of $50 \ \Omega$,$100 \ \Omega$,and $150 \ \Omega$ in a given conductivity cell. The resistance observed if they are mixed in a volume proportion which is the reciprocal of their resistances and tested in the same conductivity cell would be ............. $\Omega$.

Consider the following data.

Electrolyte	$\Lambda_m^\circ$ $(S\text{ cm}^2\text{ mol}^{-1})$
$BaCl_2$	$x_1$
$H_2SO_4$	$x_2$
$HCl$	$x_3$

$BaSO_4$ is sparingly soluble in water. If the conductivity of the saturated $BaSO_4$ solution is $x\text{ S cm}^{-1}$, then the solubility product of $BaSO_4$ can be given as (Here $\Lambda_m = \Lambda_m^\circ$)

The rusting of iron takes place as follows. Calculate $\Delta G^o$ for the net process in $kJ \ mol^{-1}$.
$2H^{+} + 2e^- + \frac{1}{2}O_2 \longrightarrow H_2O_{(l)} ; E^o = +1.23 \ V$
$Fe^{2+} + 2e^- \longrightarrow Fe_{(s)} ; E^o = -0.44 \ V$

Based on the following information,arrange four metals,$A$,$B$,$C$,and $D$,in order of increasing ability to act as reducing agents:
$(I)$ Only $C$ reacts with $1 \ M \ HCl$ to give $H_{2(g)}$.
$(II)$ When $A$ is added to a solution of the other metal salts,metallic $D$ is formed,but not $B$ or $C$.