Oxidation and reduction, the twin processes at the heart of chemical reactions, shape the dynamic landscape of chemistry. These reactions involve the transfer of electrons between atoms and molecules, leading to transformations in oxidation states and the creation of new substances. In this comprehensive article, we delve into the intricacies of 20 distinct chemical reactions, each exemplifying the captivating interplay of oxidation and reduction, complete with chemical formulas for a deeper understanding.

1. Combustion of Hydrocarbons

Reaction: CH₄ + 2O₂ → CO₂ + 2H₂O

Hydrocarbons, represented here by methane (CH₄), undergo combustion in the presence of oxygen (O₂). This process is a prime example of oxidation, as carbon in methane is oxidized to form carbon dioxide (CO₂).

2. Rusting of Iron

Reaction: 4Fe + 3O₂ + 6H₂O → 4Fe(OH)₃

Iron (Fe) reacts with oxygen (O₂) and water (H₂O) to form iron hydroxide (Fe(OH)₃), known as rust. Here, iron undergoes oxidation by losing electrons to oxygen.

3. Photosynthesis

Reaction: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

Photosynthesis is a complex biological process where carbon dioxide (CO₂) and water (H₂O), in the presence of light energy, transform into glucose (C₆H₁₂O₆) and oxygen (O₂). Carbon dioxide is reduced to glucose, while water is oxidized to release oxygen.

4. Cellular Respiration

Reaction: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy

In cellular respiration, glucose (C₆H₁₂O₆) is oxidized to produce carbon dioxide (CO₂), water (H₂O), and energy. This process powers the cells’ functions.

5. Oxidation of Metals

Reaction: 2Mg + O₂ → 2MgO

Metals like magnesium (Mg) react with oxygen (O₂) to form metal oxides, such as magnesium oxide (MgO). Here, magnesium undergoes oxidation by losing electrons to oxygen.

6. Disproportionation of Hydrogen Peroxide

Reaction: 2H₂O₂ → 2H₂O + O₂

Hydrogen peroxide (H₂O₂) can undergo disproportionation, breaking down into water (H₂O) and oxygen (O₂). Some molecules lose oxygen (oxidation), while others gain oxygen (reduction).

7. Corrosion of Copper

Reaction: 4Cu + O₂ + 2H₂O → 2Cu₂(OH)₂

Copper (Cu) reacts with oxygen (O₂) and water (H₂O) to form copper hydroxide (Cu₂(OH)₂), commonly known as verdigris. This reaction involves the oxidation of copper.

8. Reduction of Metal Ores

Reaction: Fe₂O₃ + 3CO → 2Fe + 3CO₂

Iron ore (Fe₂O₃) is reduced using carbon monoxide (CO) in a blast furnace to obtain iron (Fe) and carbon dioxide (CO₂).

9. Electroplating

Reaction: Ag⁺ + e⁻ → Ag

In silver-plating, silver ions (Ag⁺) are reduced to form solid silver (Ag) on a metal object using electricity.

10. Redox Reactions in Batteries

Reaction (Anode): Zn → Zn²⁺ + 2e⁻

Reaction (Cathode): 2MnO₂ + 2H⁺ + 2e⁻ → Mn₂O₃ + H₂O

Alkaline batteries involve redox reactions: zinc (Zn) oxidizes at the anode, releasing electrons, while manganese dioxide (MnO₂) reduces at the cathode.