From the following, identify the reaction having the top position in the EMF series (standard reduction potential) according to their electrode potential at 298 K.

1. Mg²⁺+ 2e^–$\to$Mg_(s)
2. Fe²⁺ + 2e^–$\to$ Fe_(s)
3. Au³⁺+ 3e^–$\to$Au_(s)
4. K⁺+ 1e ^–$\to$K_(s)

Standard electrode potentials are:

$F{e}^{+2}/Fe$ ,$E°$ $=$ $-0.\mathrm{44<mspace\; width="1em"></mspace>}$

$\mathrm{<mspace\; width="1em"></mspace>}F{e}^{+3}/F{e}^{+2},E°$ $=0.77$

Choose the correct observation when $F{e}^{+2},$ $F{e}^{+3}$, and Fe _(solid) are kept together:

1. $F{e}^{+3}$ increases 

2. $F{e}^{+3}$ decreases 

3. $\frac{F{e}^{+2}}{F{e}^{+3}}$ remains unchanged 

4. $F{e}^{+2}$ decreases