What's Going On When Iron Electrodes Are Electrolyzed in Sodium Hydroxide?

[tmiddlet]

I've got a question that is bugging me

If I have a concentrated sodium hydroxide solution and electrolyze it with iron electrodes, some of the possible reactions at the positive electrode are
2H₂O -> O₂ + 4H⁺+4e^-. E^o = -1.23 V
4OH^- -> O₂ + 2H₂O + 4e^-. E^o = -0.40 V
Fe -> Fe²⁺ + 2e^-. E^o = 0.44 V

and at the negative electrode, the most likely reaction is
2H₂O +2e^- -> H₂ +2OH^-. E^o = -0.88 V

Given this information, I would expect to see hydrogen gas at the negative electrode and iron hydroxide at the positive, but when I actually perform it I get oxygen and hydrogen, but no iron hydroxide. Why is this?

 

[Borek]

Reactions occur in the order from the "easiest" to the "hardest" - so as long as there is water present it will react preferentially.

 

[tmiddlet]

That's what I thought, but it is much easier to oxidize iron than either water or hydroxide according to the values I found... Why do I not get any iron hydroxide?