Class 10 Science Chapter 1 Chemical Reactions and Equations Concept Clarity MCQs with Answers

 Practice these 10 Concept Clarity MCQs to strengthen your understanding of Chapter 1. These questions are designed according to the CBSE syllabus.

Concept Clarity MCQs

Q1. Which of the following observations do not help us determine whether a chemical reaction has taken place?

a) change in state (b) change in colour (c) change in quantity (d) change in temperature 

Q2. CaO + H₂O  --> Ca(OH)₂ + Heat, Identify the type of reaction

a) Combination reaction (b) Decomposition reaction (c) Exothermic reaction (d) Both a and c 

Q3. ...................... is used for whitewashing walls.

a) Quick lime (b) Slaked lime (c) Soda lime (d) none of these 

Q4. Ca(OH)₂ reacts slowly with the ................ in air to form a thin layer of calcium carbonate on the walls.

a) Oxygen (b) Nitrogen (c) Carbon dioxide (d) All of these 

Q5. Which of the following gives a shiny finish to the walls after whitewashing.

a) Carbon dioxide (b) Calcium hydroxide (c) Calcium oxide (d) Calcium carbonate

Q6. Decomposition of vegetable matter into compost is an example of which type of reaction?

a) Exothermic reaction (b) Endothermic reaction (c) Displacement reaction (d) none of these

Q7. ......................combines with oxygen in the cells of our body to provide energy.

a) Carbon dioxide (b) Glucose (c) Starch (d) food

Q8. Ferrous sulphate crystals decompose to ferric oxide and ..............

a) Sulphur dioxide (b) Sulphur trioxide (c) both a and b (d) none of these 

Q9. Decomposition of which of the following compounds is involved in the cement industry?

a) Ferrous sulphate (b) Sodium carbonate (c) Calcium carbonate (d) All of these 

Q10. Decomposition of Lead nitrate produces which of the following?

a) Oxygen gas (b) Nitrogen dioxide (c) Lead oxide (d) All of these  

🧠 TopperGuru1 Concept Check

Before checking the answer key, ask yourself these two questions for every MCQ:

✅ Why is the correct option right?

✅ Why are the other three options wrong?

If you can explain both, your concept is truly clear. If not, revise the related NCERT concept and try again.

Remember: Real learning happens when you understand the reason, not when you memorize the answer.

✅ Answer Key

1. (c) 2. (d) 3. (b) 4. (c) 5. (d) 6. (a) 7. (b) 8. (c) 9. (c) 10. (d)