Which of the following solutions cannot be used in a salt bridge?

Using the standard electrode potentials given in Table $3.1$ of the $NCERT$ textbook,predict if the reaction between the following is feasible:
$(i)$ $Fe^{3+}_{(aq)}$ and $I^{-}_{(aq)}$
$(ii)$ $Ag^{+}_{(aq)}$ and $Cu_{(s)}$
$(iii)$ $Fe^{3+}_{(aq)}$ and $Br^{-}_{(aq)}$
$(iv)$ $Ag_{(s)}$ and $Fe^{3+}_{(aq)}$
$(v)$ $Br_{2(aq)}$ and $Fe^{2+}_{(aq)}$

$A$ device that converts the energy of combustion of fuels like hydrogen and methane directly into electrical energy is known as:

$A^{2+}_{(aq.)} + 2e^- \to A_{(s)}$ ; $E^{\circ} = 0.8 \ V$
$B^{3+}_{(aq.)} + 3e^- \to B_{(s)}$ ; $E^{\circ} = 0.6 \ V$
Using the above information,find the ion which will be deposited first at the cathode if a solution containing $A^{2+}_{(aq.)}$ and $B^{3+}_{(aq.)}$ is electrolysed.

Give the cell reaction,cell representation,and the formula for the cell potential of a copper-silver galvanic cell.

What is the reaction occurring at the anode in a $CH_4 - O_2$ fuel cell?