CG Board Class 9 Science Chapter 10 Solutions: Chemical Reactions and Equations (रासायनिक अभिक्रियाएँ एवं समीकरण) – 2026-27

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CG SCERT (Chhattisgarh Board) Class 9 Science Solutions | 2026-27 Official Edition

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Complete 100% textbook-grounded CG Board Class 9 Science Chapter 10 Solutions: Chemical Reactions and Equations (रासायनिक अभिक्रियाएँ एवं समीकरण) in Bilingual Format (English & Hindi Medium).

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Official Textbook Exercises

End-of-Chapter Exercises (Solutions)

Question 1

Multiple Choice Questions


📝 Question:

Multiple Choice Questions

💡 Solution:

(i) Which of the following reactions is taking place when hydrogen chloride is formed by reaction between hydrogen and chlorine:**

  • (a) Decomposition
  • (b) Displacement
  • (c) Combination
  • (d) Double displacement

(ii) Fe_2O3 + 2Al → Al_2O3 + 2Fe. This reaction is an example of:

  • (a) Combination
  • (b) Decomposition
  • (c) Displacement
  • (d) Double displacement

(iii) 2PbO(s) + C(s) → 2Pb(s) + CO2}(g). Which statement is true about this reaction:

  • (1) Lead is undergoing oxidation
  • (2) Carbon dioxide is undergoing oxidation
  • (3) Carbon is getting oxidized to carbon dioxide
  • (4) Lead oxide is being reduced to lead
  • (a) 1 and 2
  • (b) 3 and 4
  • (c) 2 and 3
  • (d) All

(iv) NaCl(aq) + AgNO3(aq) → AgCl↓ + NaNO3(aq). The given chemical reaction is:

  • (a) Displacement
  • (b) Combination
  • (c) Decomposition
  • (d) Double displacement

Question 2

a Substances on the LHS in a chemical…


📝 Question:

(a) Substances on the LHS in a chemical equation are called …………………………….. and those on the RHS are known as …………………………….. – Official Solution: reactants, products / , (b) …………………………….. is an example of ………………………… reaction. – Official Solution: 2NaHCO3 → Na_2CO3 + H_2O + CO2 (or CaCO3 → CaO + CO2), Decomposition / (c) The arrow between the reactants and products in a chemical equation shows the ……………………………… of a reaction. – Official Solution: direction / (d) The type of reactions where heat is absorbed during the formation of products are ……………………………. reactions. – Official Solution: endothermic / What is a chemical equation? Why should chemical equations be balanced? – Hindi Question / : ? ?

💡 Solution:

The symbolic representation of a chemical reaction using chemical symbols and formulae of reactants and products is called a chemical equation.

According to the Law of Conservation of Mass, matter can neither be created nor destroyed in a chemical reaction. Therefore, the total mass and total number of atoms of each element on the reactant side (LHS) must equal the product side (RHS).

Question 3

Write balanced chemical equations for the following reactions…


📝 Question:

Write balanced chemical equations for the following reactions: – (a) Potassium metal reacting with water to give potassium hydroxide and hydrogen gas. – (b) Nitrogen gas combines with hydrogen to form ammonia. – (c) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. – (d) Barium chloride reacts with aluminium sulphate to give a solution of aluminium chloride and a precipitate of barium sulphate. – Hindi Question / : : – (a) – (b) – (c) – (d)

💡 Solution:

  • (a) Potassium + Water:
  • 2K(s) + 2H_2O(l) → 2KOH(aq) + H2(g)↑
  • (b) Nitrogen + Hydrogen:
  • N2(g) + 3H2(g) → 2NH3(g)
  • (c) Hydrogen sulphide + Oxygen:
  • 2H_2S(g) + 3O2(g) → 2H_2O(l) + 2SO2(g)↑
  • (d) Barium chloride + Aluminium sulphate:
  • 3BaCl2(aq) + Al2(SO4)3(aq) → 2AlCl3(aq) + 3BaSO4(s)↓

Question 4

Balance the following chemical equations i C_3Hsub8sub Osub2sub…


📝 Question:

Balance the following chemical equations: – (i) C_3H8 + O2 → H_2O + CO2 – (ii) C_6H12O6 → C_2H_5OH + CO2 – (iii) Hg(NO3)2 + KI → HgI2 + KNO3 – (iv) HNO3 + Ca(OH)2 → Ca(NO3)2 + H_2O – Hindi Question / : : – (i) C_3H8 + O2 → H_2O + CO2 – (ii) C_6H12O6 → C_2H_5OH + CO2 – (iii) Hg(NO3)2 + KI → HgI2 + KNO3 – (iv) HNO3 + Ca(OH)2 → Ca(NO3)2 + H_2O

💡 Solution:

(i) Combustion of Propane:**

  • (ii) Fermentation of Glucose:
  • (iii) Mercuric nitrate + Potassium iodide:
  • (iv) Nitric acid + Calcium hydroxide:

Question 5

Write the balanced chemical equation for the following…


📝 Question:

Write the balanced chemical equation for the following and identify the type of reaction in each case: – (a) Magnesium + Iodine → Magnesium iodide – (b) Magnesium + Hydrochloric acid → Magnesium chloride + Hydrogen – (c) Zinc + Copper nitrate → Zinc nitrate + Copper – (d) Sodium hydrogencarbonate → Sodium carbonate + Carbon dioxide + Water – Hindi Question / : : – (a) + → – (b) + → + – (c) + → + – (d) → + +

💡 Solution:

  • (a) Magnesium + Iodine:
  • Balanced Equation: Mg(s) + I2(s) → MgI2(s)
  • Type of Reaction: Combination Reaction /
  • (b) Magnesium + Hydrochloric acid:
  • Balanced Equation: Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)↑
  • Type of Reaction: Displacement Reaction /
  • (c) Zinc + Copper nitrate:
  • Balanced Equation: Zn(s) + Cu(NO3)2(aq) → Zn(NO3)2(aq) + Cu(s)
  • Type of Reaction: Displacement Reaction /
  • (d) Sodium hydrogencarbonate decomposition:
  • Balanced Equation: 2NaHCO3(s) → [heat] Na_2CO3(s) + H_2O(l) + CO2(g)↑
  • Type of Reaction: Decomposition Reaction (Thermal Decomposition) /

Question 6

Why are decomposition reactions called the opposite of…


📝 Question:

Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions. – Hindi Question / : ?

💡 Solution:

In a combination reaction, two or more simple substances combine to form a single complex product.

  • Equation: 2H2(g) + O2(g) → 2H_2O(l)
  • In a decomposition reaction, a single complex reactant breaks down into two or more simpler products.
  • Equation: 2H_2O(l) → [electricity] 2H2(g) + O2(g)
  • Thus, the processes are exact inverses of each other in terms of reactants and products.

Question 7

Write one equation each for decomposition reactions where…


📝 Question:

Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity. – Hindi Question / : – ,

💡 Solution:

  1. Thermal Decomposition:
  • CaCO3(s) → [heat] CaO(s) + CO2(g)↑
  1. Photochemical Decomposition:
  • 2AgCl(s) → [sunlight] 2Ag(s) + Cl2(g)↑
  1. Electrolytic Decomposition:
  • 2H_2O(l) → [electric current] 2H2(g)↑ + O2(g)↑

Question 8

What is the difference between displacement and double…


📝 Question:

What is the difference between displacement and double displacement reactions? Write equations for these reactions. – Hindi Question / : ?

💡 Solution:

FeatureDisplacement ReactionDouble Displacement Reaction
Number of Displacements / Single displacement.Mutual double displacement.
Equation / Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)Na_2SO4(aq) + BaCl2(aq) → BaSO4(s)↓ + 2NaCl(aq)

Question 9

Give two examples of redox reactions Hindi Question


📝 Question:

Give two examples of redox reactions. – Hindi Question /

💡 Solution:

  • Example 1:
  • CuO(s) + H2(g) → Cu(s) + H_2O(l)
  • Oxidized: H2 → H_2O; Reduced: CuO → Cu.
  • Example 2:
  • ZnO(s) + C(s) → Zn(s) + CO(g)
  • Oxidized: C → CO; Reduced: ZnO → Zn.

Question 10

Explain the chemical reactions that take place in…


📝 Question:

Explain the chemical reactions that take place in the presence of sunlight. – Hindi Question /

💡 Solution:

Reactions that occur absorbing light energy are called photochemical reactions.

Question 11

Photosynthesis Plants synthesize glucose from COsub2sub and water…


📝 Question:

Photosynthesis: Plants synthesize glucose from CO2 and water in sunlight. – 6CO2(g) + 6H_2O(l) → [sunlight/chlorophyll] C_6H12O6(aq) + 6O2(g) – 2. Decomposition of Silver Chloride: White AgCl turns grey in sunlight as it decomposes into silver metal and chlorine gas. – 2AgCl(s) → [sunlight] 2Ag(s) + Cl2(g) – Hindi / : , – 1. : – 6CO2(g) + 6H_2O(l) → [ ] C_6H12O6(aq) + 6O2(g) – 2. : – 2AgCl(s) → [ ] 2Ag(s) + Cl2(g) What do you understand by precipitation reactions? Explain using examples. – Hindi Question / : ?

💡 Solution:

A reaction in which two aqueous soluble salts react to produce an insoluble solid product called a precipitate (↓) is called a precipitation reaction.

  • Example: Mixing aqueous solutions of barium chloride and sodium sulphate forms a white insoluble precipitate of barium sulphate.
  • Na_2SO4(aq) + BaCl2(aq) → BaSO4(s)↓ + 2NaCl(aq)

Question 12

Exothermic and Endothermic Reactions


📝 Question:

Exothermic and Endothermic Reactions

💡 Solution:

  • English Question: Explain exothermic and endothermic reactions through examples.
  • Hindi Question / :

Solution:

Question 13

Exothermic Reactions


📝 Question:

Exothermic Reactions

💡 Solution:

Reactions in which heat energy is released along with the formation of products.

  • Example: Combustion of natural gas: CH4(g) + 2O2(g) → CO2(g) + 2H_2O(g) + Heat

Question 14

Endothermic Reactions


📝 Question:

Endothermic Reactions

💡 Solution:

Reactions in which heat energy is absorbed during product formation.

  • Example: Thermal decomposition of limestone: CaCO3(s) + Heat → CaO(s) + CO2(g)

Question 15

Hanif burnt a magnesium ribbon using a spirit…


📝 Question:

Hanif burnt a magnesium ribbon using a spirit lamp and on the basis of his observations he said that the type of chemical reaction taking place is combination as well as exothermic as well as oxidation. Do you agree with Hanif? Give reasons for your answer and explain. – Hindi Question / : – ?

💡 Solution:

Yes, we completely agree with Hanif.**

  • Reasons:
  1. Combination Reaction: Two reactants (Mg and O2) combine together to produce a single product (MgO).
  2. Oxidation Reaction: Magnesium gains oxygen to form magnesium oxide, and loses electrons to form Mg2+ ions.
  3. Exothermic Reaction: The burning takes place with a dazzling white flame releasing intense heat and light energy.

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