Chemical Reactions and Equations — Class 10 MCQs with Answers
Class 10 CBSE Science (Chemistry) · Chapter 1
115 practice questions · 33 Easy · 42 Medium · 40 Hard · Updated
Jump to the 6 solved questions
Practise the most important Class 10 CBSE Science (Chemistry) questions from Chapter 1, "Chemical Reactions and Equations". You get 11 timed quizzes made from 115 NCERT-based MCQs, with answers and explanations. The questions are split into 33 Easy, 42 Medium and 40 Hard. Warm up on the basics, then move on to the exam-level questions that top scorers in CBSE Board exams and the JEE & NEET foundation years get right.
To score well in "Chemical Reactions and Equations", focus on clear concepts in physics, chemistry and biology basics. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This helps you stay accurate when time is short, just as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Chemical Reactions and Equations, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 10 Science (Chemistry) mastery score. Try the 6 sample questions below: tap an option to see the answer and a worked explanation. Sign in free to start practising.
Chemical Reactions and Equations — important questions & MCQs with answers (Class 10 Science (Chemistry))
6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.
0 of 6 answered
- Q1 of 6Easy
A balanced chemical equation reflects the law of:
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Answer: Conservation of mass
Explanation: Balancing ensures atoms of each element are equal on both sides — i.e., mass is conserved.
- Q2 of 6Easy
CaO + H₂O → Ca(OH)₂ is an example of:
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Answer: Combination reaction
Explanation: Two reactants combine to form a single product — combination reaction.
- Q3 of 6Medium
In 2 Cu + O₂ → 2 CuO, Cu is:
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Answer: Oxidised
Explanation: Copper combines with oxygen from air on heating to form copper oxide, 2Cu + O₂ → 2CuO, so copper gains oxygen and is oxidised.
- Q4 of 6Medium
Assertion (A): Zinc displaces copper from copper sulphate solution. Reason (R): Copper is more reactive than zinc.
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Answer: A is true but R is false
Explanation: A is true. R is false: zinc is more reactive than copper, which is why zinc can displace copper from its compound.
- Q5 of 6Hard
Rusting of iron requires the presence of:
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Answer: Both oxygen and water
Explanation: Rusting is electrochemical and needs dissolved oxygen and water acting together on iron; removing either one, as the classic rusting experiment shows, stops rust forming.
- Q6 of 6Hard
Assertion (A): In the balanced equation 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂, there are 12 oxygen atoms on each side. Reason (R): Brown fumes of nitrogen dioxide are given off when lead nitrate is heated.
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Answer: Both A and R are true but R is not the correct explanation of A
Explanation: Both are true: the left side has 2 × 6 = 12 oxygen atoms and the right side has 2 + 8 + 2 = 12. The brown fumes are an observation and do not explain the atom count.
Chemical Reactions and Equations notes: key concepts (Class 10 Science (Chemistry))
A chemical reaction rearranges atoms into new substances, and a balanced equation is the statement that no atom is created or destroyed. This chapter classifies the main reaction types and explains the everyday effects of oxidation — corrosion of metals and rancidity of food.
- Chemical reaction
- A change in which one or more substances are converted into new substances with different properties, signalled by colour change, gas evolution, precipitate or temperature change.
- Chemical equation
- A symbolic representation of a reaction with reactants on the left and products on the right, joined by an arrow showing the direction of change.
- Balancing an equation
- Adjusting coefficients so each element has the same number of atoms on both sides, as required by the law of conservation of mass.
- Law of conservation of mass
- Mass is neither created nor destroyed in a chemical reaction, which is precisely why every equation must be balanced.
- Combination reaction
- Two or more substances combine to form a single product, as when calcium oxide reacts with water to give calcium hydroxide.
- Decomposition reaction
- A single compound breaks into two or more simpler substances, driven by heat, light or electricity.
- Displacement reaction
- A more reactive element displaces a less reactive one from its compound, as iron displaces copper from copper sulphate.
- Double displacement reaction
- Two compounds exchange ions, often producing an insoluble precipitate, as in the reaction of sodium sulphate with barium chloride.
- Oxidation and reduction
- Oxidation is gain of oxygen or loss of hydrogen; reduction is the reverse. They always occur together in a redox reaction.
- Exothermic and endothermic
- Exothermic reactions release heat and warm the surroundings; endothermic reactions absorb heat and cool them.
- Corrosion
- The gradual attack of a metal by air and moisture, such as the rusting of iron, which requires both oxygen and water.
- Rancidity
- The oxidation of fats and oils in food, giving unpleasant smell and taste; prevented by antioxidants, airtight packing or flushing with nitrogen.
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Chemical Reactions and Equations — FAQs
What are the key concepts in Class 10 Science (Chemistry) Chemical Reactions and Equations?+
A chemical reaction rearranges atoms into new substances, and a balanced equation is the statement that no atom is created or destroyed. This chapter classifies the main reaction types and explains the everyday effects of oxidation — corrosion of metals and rancidity of food. Key ideas include Chemical reaction, Chemical equation, Balancing an equation, Law of conservation of mass, Combination reaction, Decomposition reaction.
What does Class 10 Science (Chemistry) Chapter 1 (Chemical Reactions and Equations) cover on XamBaaz?+
It has 115 NCERT-based MCQs on "Chemical Reactions and Equations": 33 Easy, 42 Medium and 40 Hard. Together they make 11 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE Board exams and the JEE & NEET foundation years.
Are these "Chemical Reactions and Equations" questions free to practise?+
Yes. Sign in with Google to practise "Chemical Reactions and Equations" free. Full unlimited access is ₹999/year. One year from the day you pay. You stay in Class 10 till 31 March; on 1 April your account moves up to Class 11 and the rest of your year carries over. No chapter is charged separately.
How should I revise "Chemical Reactions and Equations" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 11 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Chemical Reactions and Equations" MCQs available with answers?+
Yes. 6 sample questions are on this page with answers: tap an option, or "Show answer", to see the correct option and a step-by-step explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Chemical Reactions and Equations" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Chemical Reactions and Equations (Class 10 Science (Chemistry))?+
The questions that matter most test Chemical reaction, Chemical equation, Balancing an equation, Law of conservation of mass, Combination reaction, Decomposition reaction. This page shows 6 solved important MCQs with answers and explanations. Sign in to practise all 115 questions on the chapter as timed quizzes.
Is there an online quiz for Chemical Reactions and Equations?+
Yes — Class 10 Science (Chemistry) Chemical Reactions and Equations has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.
Are there question answers and extra questions for Chemical Reactions and Equations (Class 10 Science (Chemistry))?+
Yes. This page has 6 solved questions on Chemical Reactions and Equations, each with the correct answer and a short explanation. Sign in to practise all 115 questions on the chapter as timed quizzes.
Are there assertion–reason and case study questions for Chemical Reactions and Equations (Class 10 Science (Chemistry))?+
Yes. The Chemical Reactions and Equations question bank has 9 assertion–reason questions and 12 case-based (case study) questions in the CBSE board format, alongside the regular MCQs. Each comes with the answer and a worked explanation. Sign in to practise them in timed quizzes.