Acidic conditions and rusting (1 Viewer)

[crammy90]

anode: Fe-->Fe2+ + 2e-
cathode: 2h+ + 2e- ---> H2 0.00V
overall
Fe + 2h+ --> Fe2+ + H2
so the cathode equation here as its 0.00v means its going to go in preference of those with ve- reduction potentials. So if theses acidic conditions werent to be there i.e. no H+, what would the normal reduction reaction be? because i can see the one for rusting would be the
o2 + 2h2O + 4e- --> 4OH- 0.4V
im just wondering why if this is more likely to go why does the acidic 1 occur in the ocean
thanks

 

[Azreil]

Acidic one occurs in the ocean for a few reasons.

CO2 + H2O <-> H2CO3

According to Le Chatelier's principle, shifts to right as pressure is increased (ie as you go deeper).

Also anaerobic bacteria (of the desulfivibrio family) produce H+ ions in the ocean.

Hence the acidic one occurs in the ocean.