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 Sure, Mayank! Here's a student-friendly, CBSE Class 10–focused explanation of the types of chemical reactions, with definitions, examples, equations, and visual clues — perfect for classroom use, notes, or revision handouts.

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🔄 Types of Chemical Reactions

(Class 10 – Chapter: Chemical Reactions and Equations)

There are five major types of chemical reactions covered in CBSE Class 10:

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1. 🔗 Combination Reaction

Two or more reactants combine to form a single product.

📘 General Form:

$$A + B \rightarrow AB$$

📌 Example:

$$\text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2$$

✅ Used in whitewashing.
✅ Usually exothermic (releases heat).

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2. 💥 Decomposition Reaction

A single compound breaks down into two or more simpler substances.
Can occur due to heat, light, or electricity.

📘 General Form:

$$AB \rightarrow A + B$$

📌 Example (thermal):

$$2\text{Pb(NO}_3)_2 \xrightarrow{\text{heat}} 2\text{PbO} + 4\text{NO}_2 + \text{O}_2$$

✅ Types of decomposition:

• Thermal decomposition (heat)

• Photolytic decomposition (light)

• Electrolytic decomposition (electricity)

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3. 🔁 Displacement Reaction

A more reactive element displaces a less reactive one from its compound.

📘 General Form:

$$A + BC \rightarrow AC + B$$

📌 Example:

$$\text{Zn} + \text{CuSO}_4 \rightarrow \text{ZnSO}_4 + \text{Cu}$$

✅ Always involves reactivity series.

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4. 🔄 Double Displacement Reaction

Exchange of ions between two compounds.
Often forms a precipitate.

📘 General Form:

$$AB + CD \rightarrow AD + CB$$

📌 Example:

$$\text{BaCl}_2 + \text{Na}_2\text{SO}_4 \rightarrow \text{BaSO}_4 ↓ + 2\text{NaCl}$$

✅ Forms an insoluble precipitate → precipitation reaction.

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5. 🔥 Redox Reaction

(Oxidation + Reduction happening together)

✅ Oxidation:

Gain of oxygen / Loss of hydrogen

✅ Reduction:

Loss of oxygen / Gain of hydrogen

📌 Example:

$$\text{CuO} + \text{H}_2 \rightarrow \text{Cu} + \text{H}_2\text{O}$$

• CuO is reduced to Cu

• H₂ is oxidised to H₂O

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📘 Summary Table

Type	Description	Example
Combination	A + B → AB	CaO + H₂O → Ca(OH)₂
Decomposition	AB → A + B	2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂
Displacement	A + BC → AC + B	Zn + CuSO₄ → ZnSO₄ + Cu
Double Displacement	AB + CD → AD + CB	BaCl₂ + Na₂SO₄ → BaSO₄↓ + 2NaCl
Redox	Oxidation + Reduction together	CuO + H₂ → Cu + H₂O

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🎤 Smart Revision Tip:

Use this acronym: Co-De-Di-Do-R
Co → Combination
De → Decomposition
Di → Displacement
Do → Double Displacement
R → Redox

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