ChemCE1998Q21 Fe(2)SO4 solution has Fe(2) ion,OH- ion,2 reducing agent.Why is Fe(2) ion being discharged but not OH-,which is stronger RA?

Reduction potential
Fe3+ + e- → Fe2+, Eo = 0.77 volts,
2 H2O + O2 + 4 e- → 4 OH- , Eo = 0.4 volts,
OH- is more easier to oxidize than Fe2+, theoretically.
But, in practice, O2 needs more energy (overpotential)to produce in the electrode.
Fe2+ is more stronger RA in this solution.