Types of Chemical Reactions

Sketch Notes Developed by Jahnavi, Class 10

The image is a mind map summarizing different types of chemical reactions. Let’s go through each category step by step:

1. Combination Reactions

• These reactions occur when two or more reactants combine to form a single product.
• General formula: A + B → AB
• Examples:
  • CaO + H₂O → Ca(OH)₂ + Heat (Formation of slaked lime)
  • C + O₂ → CO₂ (Carbon combustion)
  • 2H₂ + O₂ → 2H₂O (Formation of water)

2. Decomposition Reactions

• A single compound breaks down into two or more simpler substances.
• General formula: AB → A + B
• Types:
  • Thermal Decomposition (Requires heat)
    • CaCO₃ → CaO + CO₂ (Decomposition of limestone)
    • Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂ (Lead nitrate decomposition)
  • Electrolytic Decomposition (Requires electricity)
    • 2H₂O → 2H₂ + O₂ (Electrolysis of water)
  • Photolytic Decomposition (Requires light)
    • 2AgCl → 2Ag + Cl₂ (Decomposition of silver chloride)
    • 2AgBr → 2Ag + Br₂ (Decomposition of silver bromide)

3. Displacement Reactions

• A more reactive element displaces a less reactive element from a compound.
• General formula: A + BC → AC + B
• Examples:
  • Fe + CuSO₄ → FeSO₄ + Cu (Iron displacing copper)
  • Zn + CuSO₄ → ZnSO₄ + Cu (Zinc displacing copper)
  • Pb + CuCl₂ → PbCl₂ + Cu (Lead displacing copper)

4. Double Displacement Reactions

• Two compounds exchange their ions to form two new compounds.
• General formula: AB + CD → AD + CB
• Examples:
  • Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl (Formation of an insoluble precipitate)
  • NaCl + AgNO₃ → AgCl + NaNO₃ (Precipitation of silver chloride)
  • BaCl₂ + H₂SO₄ → BaSO₄ + HCl (Formation of barium sulfate)

5. Redox (Oxidation-Reduction) Reactions

• Involves the transfer of electrons where one substance is oxidized and another is reduced.
• Examples:
  • CuO + H₂ → Cu + H₂O (Copper oxide is reduced, hydrogen is oxidized)
  • ZnO + C → Zn + CO (Zinc oxide is reduced, carbon is oxidized)
  • MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂ (Manganese dioxide undergoes redox reaction)

Summary:

• Combination → Two or more reactants combine.
• Decomposition → A compound breaks down.
• Displacement → A more reactive element replaces a less reactive one.
• Double Displacement → Exchange of ions occurs.
• Redox → Oxidation and reduction happen simultaneously.

This diagram provides a clear classification of chemical reactions with equations, making it an excellent study tool for NEET or JEE Chemistry preparation! 🚀

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