Electrochemistry

The reaction occurring at the cathodic area is:

\(\mathrm{O}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{l})+4 \mathrm{e} \rightarrow 4 \mathrm{OH}^{-}\)

The reaction occurring at the cathodic area is:

\(\mathrm{O}_2(\mathrm{~g})+4 \mathrm{H}^{+}(\mathrm{aq})+4 \mathrm{e} \rightarrow 2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) ; \mathrm{E}^0=+1.23 \mathrm{~V}\)

Reaction occurring at anodic area is:

\(2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{O}_2(\mathrm{~g})+4 \mathrm{H}^{+}+4 \mathrm{e}\)

The overall reaction occurring during the corrosion process is:

\(2 \mathrm{Fe}_{(\mathrm{S})}+3 / 2 \mathrm{O}_2(\mathrm{~g})+6 \mathrm{H}^{+} \rightarrow 2 \mathrm{Fe}^{3+}+3 \mathrm{H}_2 \mathrm{O} ; \mathrm{E}^0=-1.23 \mathrm{~V}\)