Based on the following information,arrange four metals $A, B, C$ and $D$ in order of decreasing ability to act as reducing agents:
$[I]$ Only $A, B$ and $C$ react with $1 \ M \ HCl$ to give $H_2 \ (g)$.
$[II]$ When $C$ is added to solutions of the other metal ions,metallic $B$ and $D$ are formed.
$[III]$ Metal $C$ does not reduce $A^{n+}$.

Calculate the equilibrium constant for the reaction: $Cl_{2(g)} + 2I^{-}_{(aq)} \to 2Cl^{-}_{(aq)} + I_{2(s)}$
Given: $E^o_{(Cl_2|2Cl^{-})} = 1.36 \ V$ and $E^o_{(I_2|2I^{-})} = 0.536 \ V$.

Given the values of $ᴧ^{0}$ for $KCl, KNO_3, HCl, NaOAc,$ and $NaCl$ are $149.9, 146.0, 426.2, 91.0,$ and $226.5 \, S \, cm^2 \, eq^{-1}$ respectively,calculate the value of $ᴧ^{0}$ for $HOAc$.

The molar conductivity of $0.027 \ M$ methanoic acid is $40.42 \ S \ cm^2 \ mol^{-1}$. The value of dissociation constant of this acid is
(Given $\lambda_{H^{+}}^{\circ} = 349.6 \ S \ cm^2 \ mol^{-1}$ and $\lambda_{HCOO^{-}}^{\circ} = 54.6 \ S \ cm^2 \ mol^{-1}$)

Consider the following statements pertaining to fuel cells :-
$(a)$ Hydrogen-oxygen fuel cells make use of concentrated $KOH$ solution as an electrolyte and porous graphite impregnated with platinum as electrodes.
$(b)$ The efficiency of a fuel cell is less than unity due to polarization at electrodes and the resistance offered by the electrode and the electrolyte.
$(c)$ The electrical work,assuming the cell to be working reversibly,may be represented as $-\Delta G = W_{\text{electrical}} = -\Delta H + T\Delta S$.
Which of the above statements are correct?

The number of incorrect statements from the following is:
$A.$ The electrical work that a reaction can perform at constant pressure and temperature is equal to the reaction Gibbs energy.
$B.$ $E_{cell}^0$ is dependent on the pressure.
$C.$ $\frac{dE_{cell}^0}{dT} = \frac{\Delta_{r}S^0}{nF}$.
$D.$ $A$ cell is operating reversibly if the cell potential is exactly balanced by an opposing source of potential difference.