1. A chemical reaction involves:
A) Only change in size
B) Formation of new substance
C) Change in shape only
D) Change in state only
Right Answer: B
2. Which of the following is a combination reaction?
A) CaCO₃ → CaO + CO₂
B) 2H₂ + O₂ → 2H₂O
C) Zn + HCl → ZnCl₂ + H₂
D) AgNO₃ + NaCl → AgCl + NaNO₃
Right Answer: B
3. A reaction in which a compound breaks down into simpler substances is called:
A) Combination reaction
B) Displacement reaction
C) Decomposition reaction
D) Neutralization reaction
Right Answer: C
4. Which gas is released when zinc reacts with hydrochloric acid?
A) Oxygen
B) Nitrogen
C) Hydrogen
D) Carbon dioxide
Right Answer: C
5. The reaction between acid and base to form salt and water is called:
A) Oxidation
B) Neutralization
C) Combustion
D) Reduction
Right Answer: B
6. Rusting of iron is an example of:
A) Combination reaction
B) Oxidation reaction
C) Neutralization reaction
D) Double displacement reaction
Right Answer: B
7. The reaction 2KClO₃ → 2KCl + 3O₂ is:
A) Combination reaction
B) Decomposition reaction
C) Displacement reaction
D) Combustion reaction
Right Answer: B
8. Burning of methane in oxygen is an example of:
A) Neutralization
B) Combustion
C) Decomposition
D) Reduction
Right Answer: B
9. Which of the following is a double displacement reaction?
A) Mg + O₂ → MgO
B) HCl + NaOH → NaCl + H₂O
C) Fe + CuSO₄ → FeSO₄ + Cu
D) C + O₂ → CO₂
Right Answer: B
10. Oxidation involves:
A) Gain of hydrogen
B) Loss of oxygen
C) Gain of electrons
D) Loss of electrons
Right Answer: D
11. Reduction involves:
A) Loss of oxygen
B) Gain of oxygen
C) Loss of electrons
D) Increase in valency
Right Answer: A
12. Which of the following is a displacement reaction?
A) NaCl + AgNO₃ → AgCl + NaNO₃
B) 2H₂O → 2H₂ + O₂
C) Zn + CuSO₄ → ZnSO₄ + Cu
D) CO₂ + H₂O → H₂CO₃
Right Answer: C
13. A reaction that absorbs heat is called:
A) Exothermic reaction
B) Endothermic reaction
C) Combustion reaction
D) Neutral reaction
Right Answer: B
14. Photosynthesis is an example of:
A) Exothermic reaction
B) Endothermic reaction
C) Displacement reaction
D) Neutralization
Right Answer: B
15. A reaction that releases heat is called:
A) Endothermic reaction
B) Double displacement reaction
C) Exothermic reaction
D) Decomposition reaction
Right Answer: C
16. Which of the following indicates a chemical reaction?
A) Change in color
B) Change in temperature
C) Formation of gas
D) All of these
Right Answer: D
17. The reaction between silver nitrate and sodium chloride forms:
A) NaNO₃ and AgCl
B) NaCl and AgNO₃
C) Ag and NaCl
D) Ag₂O and NaNO₃
Right Answer: A
18. Electrolysis of water is a:
A) Combination reaction
B) Decomposition reaction
C) Neutralization reaction
D) Displacement reaction
Right Answer: B
19. Corrosion is mainly caused by:
A) Reduction
B) Oxidation
C) Neutralization
D) Combustion
Right Answer: B
20. The law of conservation of mass was proposed by:
A) Dalton
B) Newton
C) Lavoisier
D) Rutherford
Right Answer: C
21. Which reaction forms a precipitate?
A) BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl
B) C + O₂ → CO₂
C) H₂ + Cl₂ → 2HCl
D) N₂ + H₂ → NH₃
Right Answer: A
22. A redox reaction involves:
A) Only oxidation
B) Only reduction
C) Both oxidation and reduction
D) Neither oxidation nor reduction
Right Answer: C
23. Burning of coal is a:
A) Decomposition reaction
B) Combustion reaction
C) Neutralization reaction
D) Displacement reaction
Right Answer: B
24. Which of the following is a chemical change?
A) Melting of ice
B) Boiling of water
C) Dissolving sugar in water
D) Burning paper
Right Answer: D
25. When calcium oxide reacts with water, it forms:
A) CaCO₃
B) Ca(OH)₂
C) CaO₂
D) CaCl₂
Right Answer: B
26. The substance that gets oxidized in a reaction is called:
A) Oxidizing agent
B) Reducing agent
C) Catalyst
D) Solvent
Right Answer: B
27. Which of the following reactions is exothermic?
A) Photosynthesis
B) Thermal decomposition
C) Respiration
D) Electrolysis
Right Answer: C
28. In the reaction Fe₂O₃ + 2Al → Al₂O₃ + 2Fe, aluminum acts as:
A) Oxidizing agent
B) Catalyst
C) Reducing agent
D) Inhibitor
Right Answer: C
29. A catalyst:
A) Is consumed in reaction
B) Changes reaction rate
C) Changes product
D) Stops reaction
Right Answer: B
30. Which type of reaction occurs when two elements exchange ions?
A) Combination
B) Decomposition
C) Double displacement
D) Combustion
Right Answer: C