Which of the following is displaced by $Fe$?

An electrochemical cell is constructed using half-cells in the direction of spontaneous change: $Fe(OH)_{2}(s) + 2e^{-} \rightarrow Fe(s) + 2OH^{-}(aq)$ $(E^{0} = -0.88 \text{ V})$ and $AgBr(s) + e^{-} \rightarrow Ag(s) + Br^{-}(aq)$ $(E^{0} = +0.07 \text{ V})$. Which of the following options is correct?

On the flow of electricity,what happens to the concentration of the anode solution in a galvanic cell?

On the basis of the information available from the reaction $\frac{4}{3} Al + O_2 \to \frac{2}{3} Al_2O_3$,$\Delta G = -827 \ kJ \ mol^{-1}$ of $O_2$,the minimum emf required to carry out an electrolysis of $Al_2O_3$ is $............... \ V$

Upon dipping a copper rod into an aqueous solution of the salt,the solution that turns blue is

The standard reduction potentials at $298 \ K$ for the following half-cells are given below:
$Cr_2O_7^{2-} + 14H^+ + 6e^- \rightarrow 2Cr^{3+} + 7H_2O$,$E^{\circ} = 1.33 \ V$
$Fe^{3+} + 3e^- \rightarrow Fe$,$E^{\circ} = -0.04 \ V$
$Ni^{2+} + 2e^- \rightarrow Ni$,$E^{\circ} = -0.25 \ V$
$Ag^+ + e^- \rightarrow Ag$,$E^{\circ} = 0.80 \ V$
$Au^{3+} + 3e^- \rightarrow Au$,$E^{\circ} = 1.40 \ V$
Consider the given electrochemical reactions. The number of metal$(s)$ which will be oxidized by $Cr_2O_7^{2-}$ in aqueous solution is $.....$