Which one of the following will increase the voltage of the cell? $(T = 298 \ K)$ :- $Sn_{(s)} + 2Ag_{(aq)}^{+} \rightarrow Sn_{(aq)}^{2+} + 2Ag_{(s)}$

Consider the cell:
$Pt_{(s)} | H_{2(g)}(1 \ atm) | H^{+}_{(aq)}, [H^{+}]=1 \ M || Fe^{3+}_{(aq)}, Fe^{2+}_{(aq)} | Pt_{(s)}$
Given: $E^0_{Fe^{3+}/Fe^{2+}} = 0.771 \ V$ and $E^0_{H^{+}/\frac{1}{2}H_2} = 0 \ V$ at $T = 298 \ K$.
If the potential of the cell is $0.712 \ V$,the ratio of concentration of $Fe^{2+}$ to $Fe^{3+}$ is $........$. (Nearest integer)

At $298 \ K$ the equilibrium constant for the reaction $M_{(s)} + 2 Ag^{+}_{(aq)} \rightarrow M^{2+}_{(aq)} + 2 Ag_{(s)}$ is $10^{15}$. What is the $E_{cell}^{\ominus}$ (in $V$) for this reaction? $\left(\frac{2.303 RT}{F}\right) = 0.06 \ V$

For the cell reaction $Zn(s) + Cu^{2+}(aq) (1.0 \, M) \to Cu(s) + Zn^{2+}(aq) (0.1 \, M)$,the measured $e.m.f.$ at $25 \, ^oC$ is $1.3 \, V$. Calculate the $E^o$ value for the cell reaction. (in $, V$)

The name of the equation showing the relation between electrode potential $(E)$,standard electrode potential $(E^o)$,and concentration of ions in solution is

For a galvanic cell reaction at $25^{\circ}C$ with $n = 4$,the standard $emf$ is $0.295 \ V$. What is the equilibrium constant for the reaction? $(F = 96500 \ C \ mol^{-1}; R = 8.314 \ J \ K^{-1} \ mol^{-1})$