Corrosion of iron is essentially an electrochemical phenomenon where the cell reactions are

Options

A. Fe is oxidised to `Fe^(2+)` and dissolved oxygen in water is reduced to `overset(Theta)(OH)`
B. Fe is oxidised to `Fe^(3+)` and `H_(2)O` is reduced to`O_(2)^(2-)`
C. Fe is oxidised to `Fe^(2+)` and `H_(2)O` is reduced to`O_(2)^(-)`
D. Fe is oxidised to `Fe^(2+)` and `H_(2)O` is reduced to`O_(2)`

Answer

a

Explanation

`FetoFe^(2+)+2e` (anode rection)
`O_(2)+2H_(2)O+4eto4OH^(-)` (cathode reaction) The overall reaction is
`2Fe + O_(2) + 2H_(2)O to 2Fe(OH)_(2)`
`Fe(OH)_(2)` may be dehydrated to iron oxide FeO, or further oxidised to `Fe(OH)_(3)` and then dehydrated nto iron rust, `Fe_(2) O_(3)`