Class 10 Science Test Paper Chapter 1 Chemical reactions and equations | GSEB Board | Detailed Solutions & Marking Scheme

 VEDANT IGNITE TEST SERIES — 2026

Class: 10 (Basic)
Subject: Science
Chapter: 1 – Chemical Reactions and Equations
Board: GSEB

Time: 45 Minutes | Maximum Marks: 30

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Section A (1 × 7 = 7 Marks)

1. Multiple Choice Questions (3 × 1 = 3 Marks)
(Write the correct option)

1. Which of the following is a combination reaction?
   (a) CaCO₃ → CaO + CO₂
   (b) 2Mg + O₂ → 2MgO
   (c) Zn + CuSO₄ → ZnSO₄ + Cu
   (d) Fe + CuSO₄ → FeSO₄ + Cu

2. The chemical formula of quick lime is:
   (a) Ca(OH)₂ (b) CaO (c) CaCO₃ (d) CaCl₂

3. Which substance is oxidized in the reaction
   Zn + CuSO₄ → ZnSO₄ + Cu?
   (a) Zn (b) Cu (c) CuSO₄ (d) SO₄

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2. Fill in the Blanks (2 × 1 = 2 Marks)
(Choose the correct word from brackets)

4. The reaction in which heat is released is called ______ reaction.
   (Endothermic / Exothermic / Neutralization)

5. The substance that undergoes reduction gains ______.
   (Oxygen / Hydrogen / Heat)

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3. True or False (2 × 1 = 2 Marks)

6. Rusting of iron is an example of oxidation.

7. A balanced chemical equation has equal number of atoms of each element on both sides.

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Section B – Short Answer (2 Marks)

(Attempt any 3 out of 5)
(3 × 2 = 6 Marks)

8. Write any two characteristics of a chemical reaction.

9. Define displacement reaction with one example.

10. What is meant by corrosion? Give one example.

11. Write the balanced chemical equation for the reaction between iron and steam.

12. What is rancidity? Mention one method to prevent it.

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Section C – Descriptive Questions (3 Marks)

(Attempt any 3 out of 5)
(3 × 3 = 9 Marks)

13. Balance the following chemical equation:
    Fe + H₂O → Fe₃O₄ + H₂

14. Explain decomposition reaction with two examples.

15. Identify the type of reaction and balance it:
    Al + Fe₂O₃ → Al₂O₃ + Fe

16. Write any three differences between oxidation and reduction.

17. Why should we balance a chemical equation? Explain with an example.

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Section D – Long Answer (4 Marks)

(Attempt any 2 out of 3)
(2 × 4 = 8 Marks)

18. Write the steps involved in balancing a chemical equation. Balance the equation:
    C₃H₈ + O₂ → CO₂ + H₂O

19. Explain exothermic and endothermic reactions with suitable examples.

20. Explain the effects of oxidation in everyday life. Write about corrosion and rancidity with examples.

Here is the DETAILED ANSWER KEY WITH MARKING SCHEME (written in plain maths/science text format, easy to copy):

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VEDANT IGNITE TEST SERIES – ANSWER KEY

Class 10 Science | Chapter: Chemical Reactions and Equations
Marks: 30

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Section A (1 × 7 = 7 Marks)

1. MCQs (3 Marks)

1. (b) 2Mg + O2 -> 2MgO [1]

2. (b) CaO [1]

3. (a) Zn [1]

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2. Fill in the Blanks (2 Marks)

4. Exothermic [1]

5. Hydrogen [1]

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3. True / False (2 Marks)

6. True [1]

7. True [1]

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Section B (3 × 2 = 6 Marks)

(Any 3 attempted. Each carries 2 marks)

8. Characteristics of Chemical Reaction (Any 2)

• Evolution of gas

• Change in colour

• Change in temperature

• Formation of precipitate

Marking:
Any two correct points = 2 marks

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9. Displacement Reaction

Definition: A reaction in which a more reactive element displaces a less reactive element from its compound.

Example:
Zn + CuSO4 -> ZnSO4 + Cu

Marking:
Definition = 1 mark
Example = 1 mark

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10. Corrosion

Definition: Slow destruction of metals due to reaction with environment (air, moisture).

Example: Rusting of iron

Marking:
Definition = 1 mark
Example = 1 mark

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11. Reaction of Iron with Steam

3Fe + 4H2O -> Fe3O4 + 4H2

Marking:
Correct balanced equation = 2 marks
(1 mark if unbalanced but correct products)

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12. Rancidity

Definition: Oxidation of fats and oils causing unpleasant smell/taste.

Prevention:

• Use of antioxidants

• Airtight containers

• Refrigeration

Marking:
Definition = 1 mark
Any one method = 1 mark

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Section C (3 × 3 = 9 Marks)

(Any 3 attempted)

13. Balance Equation

Fe + H2O -> Fe3O4 + H2

Balanced:
3Fe + 4H2O -> Fe3O4 + 4H2

Marking:
Balancing steps = 2 marks
Final correct equation = 1 mark

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14. Decomposition Reaction

Definition: A compound breaks into simpler substances.

Examples:
CaCO3 -> CaO + CO2
2H2O -> 2H2 + O2

Marking:
Definition = 1 mark
Each example = 1 mark

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15. Type & Balance Reaction

Al + Fe2O3 -> Al2O3 + Fe

Balanced:
2Al + Fe2O3 -> Al2O3 + 2Fe

Type: Displacement reaction

Marking:
Balancing = 2 marks
Type identification = 1 mark

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16. Oxidation vs Reduction (Any 3 differences)

Oxidation:

• Gain of oxygen

• Loss of hydrogen

• Loss of electrons

Reduction:

• Loss of oxygen

• Gain of hydrogen

• Gain of electrons

Marking:
Any 3 correct differences = 3 marks

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17. Need for Balancing Equation

Reason: To satisfy law of conservation of mass (mass remains same).

Example:
H2 + O2 -> H2O (unbalanced)
2H2 + O2 -> 2H2O (balanced)

Marking:
Reason = 1 mark
Example explanation = 2 marks

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Section D (2 × 4 = 8 Marks)

18. Balancing Chemical Equation (Steps + Example)

Steps:

1. Write skeletal equation

2. List atoms

3. Balance metals

4. Balance non-metals

5. Balance hydrogen and oxygen

6. Check final equation

Equation:
C3H8 + O2 -> CO2 + H2O

Balanced:
C3H8 + 5O2 -> 3CO2 + 4H2O

Marking:
Steps (any 4 correct) = 2 marks
Balancing process = 1 mark
Final correct equation = 1 mark

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19. Exothermic & Endothermic Reactions

Exothermic: Heat released
Example:
CH4 + 2O2 -> CO2 + 2H2O + heat

Endothermic: Heat absorbed
Example:
CaCO3 -> CaO + CO2

Marking:
Definitions = 2 marks
Examples = 2 marks

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20. Effects of Oxidation (Corrosion & Rancidity)

Corrosion:

• Rusting of iron

• Damage to structures

Rancidity:

• Spoilage of food

• Bad smell/taste

Marking:
Corrosion explanation = 2 marks
Rancidity explanation = 2 marks

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✅ TOTAL = 30 MARKS

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