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CBSE Class 10 Chemistry | Chapter 1: Chemical Reactions & Equations

CBSE Curriculum Aligned
Double Displacement Reactions Demonstration
1

Precipitation Reaction: BaCl₂ + Na₂SO₄

Ready to Start
BaCl₂ Solution
(Colorless)
Reaction Mixture
Forms BaSO₄ (White ppt)
Na₂SO₄ Solution
(Colorless)
BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s)↓ + 2NaCl(aq)
2

Precipitation Reaction: Pb(NO₃)₂ + KI

Ready to Start
Pb(NO₃)₂ Solution
(Colorless)
Reaction Mixture
Forms PbI₂ (Yellow ppt)
KI Solution
(Colorless)
Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s)↓ + 2KNO₃(aq)
3

Precipitation Reaction: NaOH + CuSO₄

Ready to Start
NaOH Solution
(Colorless)
Reaction Mixture
Forms Cu(OH)₂ (Blue-green ppt)
CuSO₄ Solution
(Blue)
2NaOH(aq) + CuSO₄(aq) → Cu(OH)₂(s)↓ + Na₂SO₄(aq)

NCERT Theory Concepts

Double Displacement Reaction

A chemical reaction in which two compounds exchange their ions to form two new compounds.

General Form: AB + CD → AD + CB
Examples: All reactions shown above are double displacement reactions

Precipitation Reaction

A type of double displacement reaction where an insoluble solid (precipitate) is formed.

BaSO₄: White precipitate, insoluble in water and acids
PbI₂: Yellow precipitate, photosensitive
Cu(OH)₂: Blue-green precipitate, turns black on heating

CBSE Practical Applications

Barium Meal: BaSO₄ used in X-ray imaging of digestive system
Photography: Silver compounds used in photographic films
Pigments: Lead compounds used in paints (now restricted)
Water Treatment: Precipitation used to remove impurities

CBSE Concept Check

Q1. What type of chemical reaction is BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl?

A. Combination reaction
B. Double displacement reaction
C. Decomposition reaction
D. Displacement reaction

Q2. What is the color of lead iodide precipitate?

A. White
B. Yellow
C. Blue
D. Green

Q3. Which of these is NOT a double displacement reaction?

A. BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl
B. Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
C. Zn + 2HCl → ZnCl₂ + H₂
D. 2NaOH + CuSO₄ → Cu(OH)₂ + Na₂SO₄

Q4. What is the precipitate formed when NaOH reacts with CuSO₄?

A. CuO
B. Cu(OH)₂
C. Cu
D. CuSO₄

Q5. Which precipitate is used in medical X-ray imaging?

A. PbI₂
B. Cu(OH)₂
C. BaSO₄
D. AgCl
Score: 0/5