Corrosion and Rancidity (Daily Life Importance)
Corrosion
When metal reacts with air + moisture (mainly oxygen + water vapor)
➡️ Forms a layer of oxide, which damages the metal.
Example:
Rusting of iron
4Fe + 3O₂ + 6H₂O → 4Fe(OH)₃ → Fe₂O₃·xH₂O (rust)
Prevention:
Painting
Galvanization (coating with zinc)
Oil/grease layer
Rancidity
Fats and oils in food get oxidized when exposed to air.
➡️ They smell and taste bad.
Causes:
Light
Oxygen
Heat
Prevention:
Airtight packing
Using antioxidants (like BHA/BHT)
Refrigeration