Copper from copper sulphate solution can be displaced by .............. The standard reduction potentials of some electrodes are given below:
$E^o (Fe^{2+}, Fe) = -0.44 \ V$
$E^o (Zn^{2+}, Zn) = -0.76 \ V$
$E^o (Cu^{2+}, Cu) = +0.34 \ V$
$E^o (Cr^{2+}, Cr) = -0.74 \ V$
$E^o (H^{+}, 1/2H_2) = 0.00 \ V$

The molar conductivity of a solution of a weak acid $HX$ $(0.01 \ M)$ is $10$ times smaller than the molar conductivity of a solution of a weak acid $HY$ $(0.10 \ M)$. If $\lambda_{X^{-}}^0 \approx \lambda_{Y^{-}}^0$,the difference in their $pK_a$ values,$pK_a(HX) - pK_a(HY)$,is (consider degree of ionization of both acids to be $\ll 1$)

Using the standard electrode potentials,predict if the reaction between the following is feasible:
$(a) Fe_{(aq)}^{3+} \text{ and } I_{(aq)}^{-}$
$(b) Ag_{(aq)}^{+} \text{ and } Cu_{(s)}$
$(c) Fe_{(aq)}^{3+} \text{ and } Cu_{(s)}$
$(d) Ag_{(s)} \text{ and } Fe_{(aq)}^{3+}$
$(e) Br_{2(aq)} \text{ and } Fe_{(aq)}^{2+}$

The standard electrode potentials $E^o_{(I_2/I^{-})}$,$E^o_{(Br^{-}/Br_2)}$,and $E^o_{(Fe/Fe^{2+})}$ are respectively $+0.54 \ V$,$-1.09 \ V$,and $0.44 \ V$. On the basis of the above data,which of the following processes is non-spontaneous?

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$A$. $Cd_{(s)} + 2 Ni(OH)_{3(s)} \rightarrow CdO_{(s)} + 2 Ni(OH)_{2(s)} + H_2O_{(l)}$	$I$. Primary battery
$B$. $Zn(Hg) + HgO_{(s)} \rightarrow ZnO_{(s)} + Hg_{(l)}$	$II$. Discharging of secondary battery
$C$. $2 PbSO_{4(s)} + 2 H_2O_{(l)} \rightarrow Pb_{(s)} + PbO_{2(s)} + 2 H_2SO_{4(aq)}$	$III$. Fuel cell
$D$. $2 H_{2(g)} + O_{2(g)} \rightarrow 2 H_2O_{(l)}$	$IV$. Charging of secondary battery

Choose the correct answer from the options given below.

What is a weak electrolyte? Explain the relation between the concentration of a weak electrolyte and molar conductivity with a suitable graph.