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.
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).
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.