These 30 multiple-choice questions (MCQs) on chemical reactions and equations are suitable for Class 10 students, along with solutions and explanations. Also, Help in testing your knowledge regarding chemical reactions and equations. Moreover get the NCERT Exercise Question is easy to understand 👉 Click Now
1. Which of the following represents a chemical change?
a) Melting of ice
b) Burning of wood
c) Breaking of glass
d) Dissolving sugar in water
Answer: b) Burning of wood
Explanation: Burning of wood is a chemical change as it produces new substances (carbon dioxide and water).
2. What are the substances that undergo a chemical change in a reaction called?
a) Products
b) Reactants
c) Catalysts
d) None of these
Answer: b) Reactants
Explanation: Reactants are the starting materials that undergo a chemical change to form products.
3. In a chemical reaction, what does the arrow (→) indicate?
a) Reactants
b) Products
c) Direction of the reaction
d) State of matter
Answer: c) Direction of the reaction
Explanation: The arrow indicates the direction in which the chemical reaction proceeds, from reactants to products.
4. Why is it important to balance a chemical equation?
a) To obey the law of constant proportions
b) To obey the law of conservation of mass
c) To obey the law of conservation of energy
d) To obey the law of multiple proportions
Answer: b) To obey the law of conservation of mass
Explanation: Balancing ensures that the mass of reactants equals the mass of products, adhering to the law of conservation of mass.
5. What is the coefficient of H₂ when the equation H₂ + O₂ → H₂O is balanced?
a) 1
b) 2
c) 3
d) 4
Answer: b) 2
Explanation: The balanced equation is 2H₂ + O₂ → 2H₂O.
6. Identify the correctly balanced equation:
a) N₂ + 3H₂ → 2NH₃
b) 2N₂ + H₂ → NH₃
c) N₂ + H₂ → NH₃
d) 3N₂ + H₂ → 2NH₃
Answer: a) N₂ + 3H₂ → 2NH₃
Explanation: This balanced equation follows the law of conservation of mass.
7. Which of the following is a combination reaction?
a) 2H₂ + O₂ → 2H₂O
b) CaCO₃ → CaO + CO₂
c) Zn + CuSO₄ → ZnSO₄ + Cu
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2H₂ + O₂ → 2H₂O
Explanation: Two or more substances combine to form a single product.
8. What type of reaction is represented by the equation: 2HgO → 2Hg + O₂?
a) Combination
b) Decomposition
c) Displacement
d) Double displacement
Answer: b) Decomposition
Explanation: A single compound breaks down into two or more simpler substances.
9. Identify the displacement reaction:
a) 2Na + Cl₂ → 2NaCl
b) 2KClO₃ → 2KCl + 3O₂
c) Zn + H₂SO₄ → ZnSO₄ + H₂
d) AgNO₃ + NaCl → AgCl + NaNO₃
Answer: c) Zn + H₂SO₄ → ZnSO₄ + H₂
Explanation: Zinc displaces hydrogen from sulfuric acid.
10. Which reaction is an example of an exothermic reaction?
a) C + O₂ → CO₂ + Heat
b) N₂ + 3H₂ → 2NH₃
c) BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl
d) CaCO₃ → CaO + CO₂
Answer: a) C + O₂ → CO₂ + Heat
Explanation: Exothermic reactions release heat.
11. In the reaction 2Mg + O₂ → 2MgO, magnesium is:
a) Oxidized
b) Reduced
c) Both oxidized and reduced
d) Neither oxidized nor reduced
Answer: a) Oxidized
Explanation: Magnesium gains oxygen and loses electrons, hence it is oxidized.
12. Which of the following is a reducing agent?
a) Oâ‚‚
b) Hâ‚‚
c) Clâ‚‚
d) COâ‚‚
Answer: b) Hâ‚‚
Explanation: Hydrogen can donate electrons to other substances, reducing them.
13. Which statement is true about oxidation?
a) Gain of electrons
b) Loss of oxygen
c) Loss of electrons
d) Gain of hydrogen
Answer: c) Loss of electrons
Explanation: Oxidation involves the loss of electrons.
14. Which of the following is an example of corrosion?
a) Tarnishing of silver
b) Burning of coal
c) Melting of ice
d) Rusting of iron
Answer: d) Rusting of iron
Explanation: Rusting is the corrosion of iron.
15. Which method can prevent the rancidity of food?
a) Storing food in metal containers
b) Storing food in plastic containers
c) Storing food in airtight containers
d) Storing food in warm conditions
Answer: c) Storing food in airtight containers
Explanation: Airtight containers prevent exposure to oxygen, which can cause rancidity.
16. In a neutralization reaction, which two types of substances react?
a) Acid and base
b) Acid and salt
c) Base and salt
d) Salt and water
Answer: a) Acid and base
Explanation: An acid reacts with a base to form salt and water.
17. Which is an example of a redox reaction in everyday life?
a) Boiling of water
b) Photosynthesis
c) Melting of ice
d) Evaporation
Answer: b) Photosynthesis
Explanation: Photosynthesis involves the reduction of carbon dioxide and oxidation of water.
18. Which of the following is the correct chemical equation for the reaction of sodium with water?
a) Na + H₂O → NaOH + H₂
b) 2Na + 2H₂O → 2NaOH + H₂
c) 2Na + H₂O → NaOH + H₂
d) Na + 2H₂O → 2NaOH + H₂
Answer: b) 2Na + 2H₂O → 2NaOH + H₂
Explanation: This equation is balanced and represents the reaction correctly.
19. Identify the correct representation of magnesium chloride:
a) MgCl
b) MgClâ‚‚
c) Mgâ‚‚Cl
d) Mg₂Cl₃
Answer: b) MgClâ‚‚
Explanation: Magnesium chloride is correctly represented as MgClâ‚‚.
20. What is the product when calcium carbonate decomposes?
a) Calcium oxide and carbon dioxide
b) Calcium chloride and carbon dioxide
c) Calcium oxide and oxygen
d) Calcium oxide and hydrogen
Answer: a) Calcium oxide and carbon dioxide
Explanation: The decomposition of calcium carbonate produces calcium oxide and carbon dioxide.
21. Which of the following equations represents a double displacement reaction?
a) Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
b) Zn + CuSO₄ → ZnSO₄ + Cu
c) H₂ + Cl₂ → 2HCl
d) 2KClO₃ → 2KCl + 3O₂
Answer: a) Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
Explanation: Ions are exchanged between the reactants forming new products.
22. In the equation Fe + CuSO₄ → FeSO₄ + Cu, which element is reduced?
a) Iron
b) Copper
c) Sulfur
d) Oxygen
Answer: b) Copper
Explanation: Copper ion gains electrons and is reduced.
23. Which process involves the oxidation of food?
a) Rancidity
b) Corrosion
c) Neutralization
d) Photosynthesis
Answer: a) Rancidity
Explanation: Rancidity is the oxidation of fats and oils in food.
24. Which method can be used to prevent corrosion of iron?
a) Galvanization
b) Electroplating
c) Alloying
d) All of the above
Answer: d) All of the above
Explanation: These methods can protect iron from corrosion.
25. Which reaction is used in the manufacturing of ammonia?
a) Haber’s process
b) Contact process
c) Solvay process
d) Ostwald process
Answer: a) Haber’s process
Explanation: Haber’s process is used for the synthesis of ammonia.
26. What type of reaction is Fe + S → FeS?
a) Combination
b) Decomposition
c) Displacement
d) Double displacement
Answer: a) Combination
Explanation: Two reactants combine to form a single product.
27. Which of the following reactions is an example of an endothermic reaction?
a) Photosynthesis
b) Combustion
c) Respiration
d) Neutralization
Answer: a) Photosynthesis
Explanation: Photosynthesis absorbs energy from sunlight.
28. Which gas is evolved when hydrochloric acid reacts with sodium carbonate?
a) Oxygen
b) Carbon dioxide
c) Hydrogen
d) Chlorine
Answer: b) Carbon dioxide
Explanation: The reaction produces carbon dioxide gas.
29. Which of the following substances can act as both an oxidizing and a reducing agent?
a) Hâ‚‚O
b) Hâ‚‚Oâ‚‚
c) Oâ‚‚
d) COâ‚‚
Answer: b) Hâ‚‚Oâ‚‚
Explanation: Hydrogen peroxide can act as both an oxidizing and a reducing agent.
30. Which of the following reactions represents the oxidation of hydrogen?
a) 2H₂ + O₂ → 2H₂O
b) H₂ + Cl₂ → 2HCl
c) H₂ + Br₂ → 2HBr
d) H₂ + I₂ → 2HI
Answer: a) 2H₂ + O₂ → 2H₂O
Explanation: Hydrogen reacts with oxygen to form water, and hydrogen is oxidized.
These questions cover a broad range of topics within chemical reactions and equations, ensuring a comprehensive understanding for Class 10 students.