50 MCQs from Chemical Reactions and Equations Class 10 With Answers

Students preparing for Class 10 Science exams often look for objective questions to test their understanding of concepts. This MCQ collection from the chapter Chemical Reactions and Equations helps you revise important reactions, types of chemical changes, balancing of equations, corrosion and rancidity easily.

This MCQ set is based on the NCERT Book and follows the latest CBSE exam pattern for objective questions.

 

Chemical Reactions and Equations MCQs

Q1. A chemical reaction is indicated by:

(a)       Change in size

(b)      Formation of a new substance

(c)       Change in shape

(d)      Melting

Correct answer - (b) Formation of a new substance

Q2. Which is NOT an indicator of a chemical reaction?

(a)       Change in colour

(b)      Evolution of gas

(c)       Change in temperature

(d)      Change in mass

Correct answer – (d)      Change in mass

Q3. Magnesium burns in air to form

(a)       MgO

(b)      MgCO₃

(c)       MgCl₂

(d)      Mg(OH)₂

Correct answer - (a) MgO

Q4. Burning of magnesium ribbon is a:

(a)       Decomposition reaction

(b)      Combination reaction

(c)       Displacement reaction

(d)      Double displacement reaction

Correct answer- (b) Combination reaction

Q5. The white as formed after burning magnesium is:

(a)       Magnesium nitrate

(b)      Magnesium sulphate

(c)       Magnesium oxide

(d)      Magnesium carbonate

Correct answer- (c)  Magnesium oxide

Q6. A skeletal equation is:

(a)       Balanced equation

(b)      Unbalanced equation

(c)       Word equation

(d)      Ionic equation

Correct answer- (b) Unbalanced equation

Q7. The law of conservation of mass is satisfied when the equation is:

(a)       Written

(b)      Balanced

(c)       Word form

(d)      None of these

Correct answer - (b) Balanced

Q8. Zn  + H₂SO₄ →ZnSO₄ + H₂ is a :

(a)       Combination reaction

(b)      Decomposition reaction

(c)       Displacement reaction

(d)      Double displacement reaction

Correct answer- (c)  Displacement reaction

Q9. Which gas is evolved when zinc reacts with dilute acid?

(a)       Oxygen

(b)      Hydrogen

(c)       Nitrogen

(d)      Carbon dioxide

Correct answer - (b) Hydrogen

Q10. CaO + H₂O →Ca(OH)₂ is:

(a)       Endothermic reaction

(b)      Displacement reaction

(c)       Redox reaction

(d)      Combination reaction

Correct answer - (d) Combination reaction

Q11. Reaction of CaO with water releases:

(a)       Light

(b)      Heat

(c)       Sound

(d)      Gas

Correct answer - (b) Heat

Q12. Which compound is used for whitewashing walls?

(a)       CaCO₃

(b)      Ca(OH)₂

(c)       CaO

(d)      CaCl₂

Correct answer - (b) Ca(OH)₂

Q13. What is formed when Ca(OH)₂ reacts with CO₂?

(a)       CaO

(b)      CaCl₂

(c)       CaCO₃

(d)      CaSO₄

Correct answer - (c) CaCO3

Q14. On heating ferrous sulphate crystals, a smell similar to which substance is produced?

(a)       Burning Sulphur

(b)      Chlorine

(c)       Ammonia

(d)      Hydrogen

Correct answer - (a) Burning Sulphur

Q15. What is the solid product formed when FeSO₄ is heated strongly?

(a)       FeO

(b)      Fe₂O₃

(c)       Fe₃O₄

(d)      FeCl₃

Correct answer - (b) Fe₂O₃

Q16. What are the products formed when CaCO₃ is heated?

(a)       CaO + CO₂

(b)      Ca(OH)₂

(c)       CaCl₂

(d)      CaSO₄

Correct answer - (a) CaO + CO2

17. Brown fumes observed on heating Pb(NO₃)₂ are of:

(a) NO

(b) NO₂

(c) CO₂

(d) SO₂

Correct answer - (b) NO₂

Q18. Electrolysis of water is an example of which type of reaction?

(a)       Combination reaction

(b)      Decomposition reaction

(c)       Displacement reaction

(d)      Redox reaction

Correct answer - (b) Decomposition reaction

Q19. What is the ratio of hydrogen and oxygen gases obtained during the electrolysis of water?

(a)       1:1

(b)      1:2

(c)       2:1

(d)      3:1

Correct answer -(c)  2:1

Q20. Silver chloride turns grey when exposed to:

(a)       Heat

(b)      Air

(c)       Sunlight

(d)      Water

Correct answer - (c) Sunlight

Q21. The reaction 2SgCl →2Ag + Cl₂ occurs due to:

(a)       Thermal decomposition

(b)      Photochemical decomposition

(c)       Electrolysis

(d)      Displacement

Correct answer - (b) Photochemical decomposition

Q22. What colour change is observed when an iron nail is dipped in copper sulphate solution?

(a)       Turns blue

(b)      Turns green

(c)       Turns brown

(d)      Turns black

Correct answer - (b) Turns green

Q23. The reaction Fe + CuSO₄  →  FeSO₄ + Cu is classified as:

(a)       Double displacement reaction

(b)      Combination reaction

(c)       Displacement reaction

(d) Neutralisation reaction

Correct answer - (c) Displacement reaction

Q24. Which substance forms a white precipitate when Na₂SO₄ reacts with BaCl₂?

(a)       NaCl

(b)      BaSO₄

(c)       BaCl₂

(d)      Na₂SO₄

Correct answer -  (b)      BaSO₄

Q25.The reaction in which an insoluble solid substance is formed is called:

(a)       Combination reaction

(b) Neutralisation reaction

(c)       Precipitation reaction

(d)      Decomposition reaction

Correct answer- (c)  Precipitation reaction

Q26. The reaction CuO + H₂ →Cu + H₂O is an example of :

(a)       Oxidation

(b)      Reduction

(c)       Redox reaction

(d)      Decomposition

Correct answer - (c) Redox reaction

Q27.  In the reaction CuO + H₂ →Cu + H₂O, what happens to copper oxide?

(a)       Oxidation

(b)      Reduction

(c)       Redox

(d)      No change

Correct answer - (b) Reduction

Q28. Oxidation is defined as:

(a)       Gain of hydrogen

(b)      Gain of oxygen

(c)       Loss of hydrogen

(d)      Loss of oxygen

Correct answer - (b) Gain of oxygen

Q29. Rusting of iron is an example of:

(a)       Reduction

(b)      Rancidity

(c)       Corrosion

(d)      None of the above

Correct answer - (c) Corrosion

Q30. Rancidity occurs due to which process?

(a)       Reduction

(b) Neutralisation

(c)       Cooling

(d)      Oxidation of fats and oils

Correct answer - (d) Oxidation of fats and oils

Q31. Chips packets are flushed with nitrogen gas to prevent:

(a)       Reduction

(b)      Oxidation

(c)       Decomposition

(d)      Nutralisation

Correct answer - (b) Oxidation

Q32. Respiration is considered what type of reaction?

(a)       Endothermic reaction

(b)      Neutral

(c)       Exothermic reaction

(d)      Decomposition reaction

Correct answer- (c)  Exothermic reaction

Q33. Burning of natural gas is an example of:

(a)       Endothermic reaction

(b)      Exothermic reaction

(c)       Decomposition reaction

(d)      Displacement reaction

Correct answer - (b) Exothermic reaction

Q34. Which method is commonly used to balance a chemical equation?

(a)       Trial and error method

(b)      Hit and trail method

(c)       Guess method

(d)      None of these

Correct answer - (b) Hit and trail method

Q35. The state symbol (aq) in a chemical equation represents:

(a)       Solid

(b)      Liquid

(c)       Aqueous solution

(d)      Gas

Correct answer - (c) Aqueous solution

Q36. The state symbol (g) represents:

(a)       Gas

(b)      Gel

(c)       Both above

(d)      None

Correct answer - (a) Gas

Q37. A reaction in which two or more substances combine to form a single product is called:

(a)       Decomposition reaction

(b)      Combination reaction

(c)       Displacement reaction

(d)      Double displacement reaction

Correct answer- (b) Combination reaction

Q38. A reaction that requires absorption of energy is known as:

(a)       Exothermic reaction

(b)      Endothermic reaction

(c)       Displacement reaction

(d)      Redox reaction

Correct answer - (b) Endothermic reaction

Q39. The black coating formed on copper when heated in air is:

(a)       CuO

(b)      Cu₂O

(c)       CuCO₃

(d)      CuSO₄

Correct answer - (a) CuO

Q40. Why is magnesium ribbon cleaned before burning in the air?

(a)       To remove dust particles

(b)      To remove the oxide layer

(c)       To remove moisture

(d)      To remove carbon layer

Correct answer - (b) To remove the oxide layer

Q41. The reaction in which a single compound breaks into two or more simpler substances is called:

(a)       Combination reaction

(b)      Displacement reaction

(c)       Decomposition reaction

(d)      Double displacement reaction

Correct answer - (c) Decomposition reaction

Q42.  Decomposition of silver chloride in sunlight is an example of :

(a)       Thermal decomposition

(b)      Electrolysis

(c)       Photochemical decomposition

(d)      Displacement reaction

Correct answer- (c)  Photochemical decomposition

Q43. Which reaction is used in white and black photography?

(a)       Electrolysis of water

(b)      Decomposition of AgCl in sunlight

(c)       Rusting of iron

(d)      Burning of magnesium

Correct answer- (b) Decomposition of AgCl in sunlight

Q44.  The green colour of ferrous sulphate crystals changes to brown on heating due to the formation of:

(a)       FeO

(b)      Fe₂O₃

(c)       Fe₃O₄

(d)      FeCl₃

Correct answer- (b) Fe₂O₃

Q45. The reaction CaCO₃ → CaO + CO₂ is used in industries for making:

(a)       Glass

(b)      Cement

(c)       Soap

(d)      Salt

Correct answer - (b) Cement

Q46. In the reaction Fe + CuSO4 → FeSO4 + Cu, iron is:

(a)       Reduced

(b)      Oxidised

(c)       Unchanged

(d)      None of these

Correct answer- (b) Oxidised

Q47. The reaction Na₂SO₄ + BaCl₂ →BaSO₄ + 2NaCl is an example of:

(a)       Combination reaction

(b)      Displacement reaction

(c)       Double displacement reaction

(d)      Decomposition reaction

Correct answer - (c) Double displacement reaction

Q48. Which of the following is an example of corrosion?

(a)       Burning of coal

(b)      Rusting of iron

(c)       Digestion of food

(d)      Burning of magnesium

Correct answer - (b) Rusting of iron

Q49. Rancidity can be prevented by:

(a)       Heating the food

(b)      Keeping food in the open air

(c)       Storing food in airtight containers

(d)      Adding water

Correct answer - (c) Storing food in airtight containers

Q50. A balanced chemical equation ensures:

(a)       Equal volume of substances

(b)      Equal number of molecules

(c)       Law of conservation of mass

(d)      None of the above

Correct answer - (c) Law of conservation of mass

Topics Covered in These MCQs

These questions cover all the important topic form the chapter Chemical Reaction and Equations:

    ·     Indicators of chemical reactions

    ·     Writing and balancing chemical equations (Hit and trial method)

    ·     Combination, decomposition, displacement and double displacement reactions.

    ·     Exothermic and endothermic reactions

    ·     Oxidation, reduction and redox reactions

Conclusion

Practising MCQs from Chemical Reactions and Equations help student quickly revise important reactions, concepts and NCERT activities. These questions are designed exactly as per the CBSE exam pattern and are very useful for quick self-assessment before exams.