Process of Rusting

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What is Rusting ?

Rusting is a chemical process in which iron reacts with oxygen and water (moisture) in the environment to form a reddish-brown substance called rust.

Chemical Reaction of Rusting

4Fe+3O₂+6H₂O→4Fe(OH)₃→Fe₂O₃⋅_xH₂O (Rust)

• Fe = Iron


• O₂ = Oxygen from air


• H₂O = Water or moisture


• Fe₂O₃·xH₂O = Hydrated iron(III) oxide (Rust)

Conditions Required for Rusting

1. Presence of Water or Moisture


2. Presence of Oxygen


3. Iron or materials containing iron

Type of Reaction

• Oxidation reaction


• Redox reaction


• Corrosion (general category of rusting)

Effects of Rusting

• Weakens iron structures (like bridges, machines, railings)


• Leads to loss of metal and costly repairs


• Reduces the life and efficiency of metallic items

Prevention of Rusting

1. Painting – Prevents air and moisture contact


2. Oiling or Greasing – Protects machine parts


3. Galvanization – Coating iron with zinc


4. Alloying – Using stainless steel instead of pure iron


5. Using anti-rust solutions (e.g., phosphate coating)