At $298 \ K$,the equilibrium constant is $2 \times 10^{15}$ for the reaction:
$Cu_{(s)} + 2 Ag^{+}_{(aq)} \rightleftharpoons Cu^{2+}_{(aq)} + 2 Ag_{(s)}$
The equilibrium constant for the reaction $\frac{1}{2} Cu^{2+}_{(aq)} + Ag_{(s)} \rightleftharpoons \frac{1}{2} Cu_{(s)} + Ag^{+}_{(aq)}$ is $x \times 10^{-8}$. The value of $x$ is (Nearest Integer).

Which one of the following statements is correct?

For the reaction $4B_{(s)} + 3O_{2(g)} \rightarrow 2B_2O_{3(g)}$,the standard cell potential is $E^o_{cell} = 1.433 \ V$. Calculate the molar entropy $(S_m^o)$ of oxygen gas in $J/K \ mol$.
Given:
$(\Delta_fH^o)_{B_2O_3(g)} = -840 \ kJ/mol$
$(S_m^o)_{B_2O_3(g)} = 280 \ J/K \ mol$
$(S_m^o)_{B(s)} = 10 \ J/K \ mol$
Assume $\Delta_rG^o = -nFE^o_{cell}$ and $\Delta_rG^o = \Delta_rH^o - T\Delta_rS^o$ at $T = 298 \ K$.

Using the standard electrode potentials given in the Table $8.1$,predict if the reaction between the following is feasible:
$(a)$ $Fe^{3+}_{(aq)}$ and $I^{-}_{(aq)}$
$(b)$ $Ag^{+}_{(aq)}$ and $Cu_{(s)}$
$(c)$ $Fe^{3+}_{(aq)}$ and $Cu_{(s)}$
$(d)$ $Ag_{(s)}$ and $Fe^{3+}_{(aq)}$
$(e)$ $Br_{2(aq)}$ and $Fe^{2+}_{(aq)}$

For a spontaneous reaction,the $\Delta G$,equilibrium constant $K$,and $E_{Cell}^{o}$ will be respectively:

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.