The formation of rust on the surface of iron occurs through the reaction (s) .

Options

A. ` Fe^(2+) (aq) + O_2 (g) + 4H_2 O(l) rarr 2Fe_2 O_3 (s) + 8 H^+`
B. `Fe (s) rarr Fe^(2+) (aq) = 2e ^(-) (at anode )
C. `O_2 (g) + 4 H^+ (aq) 4e^- rarr 2H_2 O` (l) (at cathode)
D. all of these above

Answer

B

Explanation

Fe is active metal and is oxidised to ` Fe^(2+),Fe^2+) , Fe^(2+)` is dissolved in ` O_2` in acidic medium (or alkaline medium) forming ` Fe_2 O_3(s) -` rust.