Corrosion and Rancidity

Part of: Class 10 Science Notes - Chemical Reactions and Equations

1. Corrosion

Corrosion is the gradual deterioration of metals due to chemical reactions, usually oxidation.

Examples of Corrosion

1. Rusting of Iron:

$4\text{Fe}+3{\text{O}}_2+6{\text{H}}_2\text{O}⟶4{\text{Fe(OH)}}_3$

• Observation: Formation of $4{\text{Fe(OH)}}_3$, which is reddish-brown in color.
• Prevention: Can be prevented by galvanization (coating the iron with a layer of Zinc).

1. Tarnishing of Copper: Color changes from red to green.
2. Tarnishing of Silver: Color changes from grey to black.

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2. Why Corrosion is an Issue

• It causes damage to most metal materials, especially those made of iron.
• This causes serious problems in infrastructure and industry.
• Every year, an enormous amount of money is spent to replace such corroded materials.

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3. Rancidity

Rancidity occurs due to the oxidation of fats and oils in food.

• Effect: Oxidation makes fats and oils rancid, changing their smell and taste.
• Prevention: To prevent this, antioxidants are added to food.
• Example: An example of a common antioxidant used in food packaging is Nitrogen.

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