Oxidation & Reduction
“Oxidation and reduction are chemical processes that involve the transfer of electrons, and are fundamental to redox reactions.”
What is Oxidation?
Oxidation is the process in which a substance:
- Loses electrons
- Gains oxygen
- Loses hydrogen
Example: Fe → Fe²⁺ + 2e⁻ (Iron gets oxidized)
What is Reduction?
Reduction is the process in which a substance:
- Gains electrons
- Loses oxygen
- Gains hydrogen
Example: Cu²⁺ + 2e⁻ → Cu (Copper ion gets reduced)
Redox Reactions
Reactions where oxidation and reduction occur simultaneously are called redox (reduction-oxidation) reactions.
Example:
Zn + CuSO₄ → ZnSO₄ + Cu
- Zn is oxidized (loses electrons)
- Cu²⁺ is reduced (gains electrons)
Oxidizing and Reducing Agents
- Oxidizing Agent: Substance that causes oxidation and gets reduced itself. (e.g., KMnO₄, Cl₂)
- Reducing Agent: Substance that causes reduction and gets oxidized itself. (e.g., H₂, CO)
Real-life Examples
- Rusting of Iron: Iron reacts with oxygen and moisture – oxidation.
- Combustion: Burning of fuels involves oxidation.
- Photosynthesis: CO₂ is reduced, H₂O is oxidized.
Previous Year Questions
- SSC CGL 2019: What happens during oxidation?
- Loss of electrons
- RRB JE 2018: In redox reactions, the substance gaining electrons is?
- Reduced
- HSSC JE 2021: Which is an oxidizing agent?
- Potassium permanganate (KMnO₄)
Tip: Remember OIL RIG – “Oxidation Is Loss, Reduction Is Gain” of electrons.
Conclusion
Oxidation and reduction reactions are vital to many processes in chemistry and biology. Understanding how electrons are transferred helps explain everything from corrosion and respiration to industrial processes and energy generation.