Observe the following picture a write down the chemical reaction with explanation:
Question 5
The chemical reaction shown here is rusting. Rusting is a complex electrochemical reaction. Different regions on the surface of iron become anode and cathode.
  1. First, Fe is oxidised to Fe2+ in the anode region.
    Fe (s) ⟶ Fe2+(aq) + 2 e-
  2. O2 is reduced to form water in the cathode region.
    O2 (g) + 4H+ (aq) + 4 e- ⟶ 2H2O (l)

      When Fe2+ ions migrate from the anode region they react with water and further get oxidised to form Fe3+ ions.
      A redish coloured hydrated oxide is formed from Fe3+ ions. It is called rust. It collects on the surface.
    2Fe3+(aq) + 4H2O (l) ⟶ Fe2O3 · H2O (s) + 6H+ (aq)
4 Marks

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18 August 2019 at 17:45