(vii) Complete the process of iron rusting by filling the blanks. Suggest a way
prevent the process.
The iron rust is formed due to
reaction. Different regions on iron
surface become anode and cathode.
• Reaction on anode region : Fes - Fe²+ (aq) + 2e
• Reaction on cathode region : 02(e)+ 4H+ (aq) + ...--------
When Fe2+ ions migrate from anode region they react with ....... to
form Fe3+ ions.
A reddish coloured hydrated oxide is formed from ions. It is
called rust.
2Fe3+ (aq) + 4H20) — +----------
A way to prevent rusting ..
+ 6H
(ag)
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Complete the process of iron rusting by filling the blanks. Suggest a way to prevent the process.
First of all, iron is oxidized to Fe²⁺(aq) at an anode on the surface of the iron. Oxygen is reduced to water at a cathode on the surface of the iron.
- Electrons are transferred from the anode to the cathode through the electrically conductive metal like copper,etc.
- Water acts as a solvent for the Fe²⁺ that is produced in the process. Rust whose formula is Fe₂O₃•xH₂O is formed by the oxidation of Fe₂⁺ by atmospheric oxygen.
- Iron metal acts as the anode and gets oxidized to Fe₂⁺ whereas oxygen is reduced to water at the cathode.
Therefore, answer to this question is :
- The iron rust is formed due to corrosion reaction. Different regions on iron surface become anode and cathode.
- Reaction on anode region : Fe(s) -> Fe²⁺ (aq) + 2e ⁻
- Reaction on cathode region : 0₂(g)+ 4H⁺(aq) + 4e⁻ -> 2H₂O(l)
- When Fe²⁺ ions migrate from anode region they react with hydrogen ions and atmospheric oxygen to form Fe³⁺ ions.
- A reddish coloured hydrated oxide is formed from ions. It is
called rust (Fe₂O₃•xH₂O).
- 2Fe³⁺ (aq) + 4H₂0 — +----------
Correct reaction is:
Fe³⁺(aq) + 3OH⁻(aq) -> Fe(OH)₃(s)
2Fe(OH)₃(s) -> Fe₂O₃•H₂O(s) + 2H₂O(l)
where : Fe₂O₃•H₂O(s) is rust.
- A way to prevent rusting : GALVANIZATION
Galvanization is the process of applying a protective zinc coating to steel or iron in order to prevent premature rust and corrosion.
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