Chemical Reactions and Equations Class 10 Extra Questions - Free PDF
Chemical Reactions and Equations Class 10 Extra Questions: The chapter Chemical Reactions and Equations is one of the most important and interesting chapters in Class 10 Science. It introduces you to the world of chemistry where everyday changes like cooking, rusting, and burning are explained through reactions. This chapter not only helps you understand how substances change into new substances but also teaches you to write and balance chemical equations properly. To help practise in a more good way, students can consider mind map for class 10 cbse maths chemical reactions and equations during revision sessions.
Every year, this chapter appears in CBSE Board exams through 1, 2, 3 and 5-mark questions. Questions are often picked from common reactions, balancing equations, and application-based topics like corrosion and displacement reactions. If you solve chemical reactions and equations extra questions regularly, your chances of scoring full marks in this chapter become much higher. A CBSE Class 10 revision book will also help you cover the full syllabus properly.
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What is a Chemical Reaction?
A chemical reaction is a process where one or more substances (called reactants) change into new substances (called products) with different properties. For example, when a magnesium ribbon burns in air, it forms magnesium oxide, which is a chemical reaction.
Examples of changes during a chemical reaction:
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Change in state
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Change in colour
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Evolution of gas
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Change in temperature
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Formation of a precipitate
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Chemical Equations
A chemical equation is a simple way to show a chemical reaction using symbols and formulas. For example: Mg+O2→MgO
This shows that magnesium (Mg) reacts with oxygen (O₂) to form magnesium oxide (MgO).
Chemical equations help in clearly understanding which elements or compounds are reacting and what products are being formed.
These equations can be written in two forms:
Word equation: where names of substances are written.
e.g., Magnesium + Oxygen → Magnesium oxide
Balanced chemical equation, where correct chemical formulas and symbols are used and atoms are balanced on both sides.
Balancing Chemical Equations
According to the Law of Conservation of Mass, the total number of atoms for each element must be the same on both sides of the equation. That’s why chemical equations need to be balanced.
Balancing helps to show that matter is neither created nor destroyed in a chemical reaction.
Example (balanced): 2Mg+O2→2MgO
Check Out: CBSE Class 10th Question Banks
Chemical Reactions and Equations Class 10 Extra Questions
As we know, Chemical Reactions and Equations is one of the most important chapters in Class 10 Science. Every year, several questions from this chapter are asked in the board exams. These questions can be in the form of definitions, balanced equations, types of reactions, or real-life applications like rusting and rancidity. So, having a clear understanding of the basics and enough practice is very important to score well.
To help students with this, PW has brought free PDFs that include detailed notes and chemical reactions and equations extra questions for Class 10. These resources are specially made to give you more practice, clear your doubts, and make your basics stronger. Practising these chemical reactions and equations questions will not only help in board exam preparation but will also build a strong base for future Science studies.
Q1. Which of the following gases is used to store fat and oil-containing foods for a long time?
- Carbon dioxide
- Oxygen
- Nitrogen
- Neon
Answer:
(3) Nitrogen gas is used to store fat and oil-containing foods for a long time. Nitrogen helps to prevent oxidation and spoilage, extending the shelf life of these products.
Q2. The chemical reaction between Hydrogen sulphide and iodine to give Hydrogen iodide and sulphur is given below:
H 2 S + I 2 → 2HI + S. The reducing and oxidising agents involved in this redox reaction are:
- Iodine and sulphur, respectively
- Iodine and hydrogen sulphide, respectively
- Sulphur and iodine, respectively
- Hydrogen sulphide and sulphur, respectively
Answer:
(2) Iodine is the oxidizing agent, and hydrogen sulfide is the reducing agent in the reaction mentioned above.
In this reaction, iodine (I₂) gains electrons (is reduced) while hydrogen sulfide (H₂S) loses electrons (is oxidized), resulting in the formation of hydrogen iodide (HI) and sulfur (S).
Short Answer Type Questions
Q1. Write the balanced chemical equations for the following reactions and identify the type of reaction in each case.
(a ) Nitrogen gas is treated with hydrogen gas in the presence of a catalyst at 773K to form ammonia gas.
(b ) Sodium hydroxide solution is treated with acetic acid to form sodium acetate and water.
(c ) Ethanol is warmed with ethanoic acid to form ethyl acetate in the presence of concentrated H 2 SO 4 .
(d) Ethene is burnt in the presence of oxygen to form carbon dioxide and water and releases heat and light.
Answer:
(a )
It is an addition reaction.
(b ) NaOH (aq) + CH 3 COOH (aq) → CH 3 COONa (aq) + H 2 O (l)
It is a double displacement or a neutralisation reaction.
(c )
It is a double displacement or an esterification reaction.
(d ) C 2 H 4 (g) + 3 O 2 (g) → 2 CO 2 (g) + 2 H 2 O (g) + Heat + light
It is a redox or a combustion reaction.
Q2. Write the balanced chemical equations for the following reactions and identify the type of
reaction in each case.
(a ) In the thermite reaction, iron (III) oxide reacts with aluminium and gives molten iron and aluminium oxide.
(b ) Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride.
(c ) Chlorine gas is passed in an aqueous potassium iodide solution to form potassium
chloride solution and solid iodine.
(d ) Ethanol is burnt in the air to form carbon dioxide and water and releases heat.
Answer:
(a ) Fe 2 O 3 (s) + 2 Al (s) → Al 2 O 3 (s) + 2 Fe (l) + Heat It is a displacement or redox reaction. (b ) 3 Mg (s) + N 2 (g) → Mg 3 N 2 (s) It is a combination reaction. (c ) 2 KI (aq) + Cl 2 (g) → 2 KCl (aq) + I 2 (s)
Q3. Complete the missing components / variables given as x and y in the following reactions
(a) Pb(NO 3 ) 2 (aq) + 2 KI (aq) → Pbl 2 (x) + 2 KNO 3 (y) (b) Cu (s) + 2 AgNO 3 (aq) → Cu(NO 3 ) 2 (aq) + x(s) (c) Zn (s) + H 2 SO 4 (aq) → ZnSO 4 (x) + H 2 (y) (d)
Answer:
(a) Pb(NO 3 ) 2 (aq) + 2 KI (aq) → Pbl 2 (s) + 2 KNO 3 (aq) (b) Cu (s) + 2 AgNO 3 (aq) → Cu(NO 3 ) 2 (aq) + 2 Ag(s) (c) Zn (s) + H 2 SO 4 (aq) → ZnSO 4 (aq) + H 2 (g) (d)
(a) Decomposition of ferrous sulphate (b) Dilution of sulphuric acid (c) Dissolution of sodium hydroxide in water (d) Dissolution of ammonium chloride in water
Answer:
(a) The decomposition of ferrous sulfate is an example of an endothermic reaction because heat is absorbed during this reaction. (b) The dilution of sulfuric acid is an example of an exothermic reaction because heat is released during this process. (c) The dissolution of sodium hydroxide in water is an example of an exothermic reaction because heat is released when sodium hydroxide dissolves. (d) The dissolution of ammonium chloride in water is an example of an endothermic reaction because heat is absorbed during this process.
Q5. Identify the reducing agent in the following reactions
(a ) 4 NH 3 + 5 O 2 → 4 NO + 6 H 2 O (b ) H 2 O + F 2 → HF + HOF (c ) Fe 2 O 3 + 3 CO → 2 Fe + 3 CO 2 (d ) 2 H 2 + O 2 → 2 H 2 O
Answer:
(a ) Here, ammonia (NH 3 ) is the reducing agent. (b ) Here, water (H 2 O) is the reducing agent. (c ) Here, carbon monoxide (CO) is the reducing agent. (d ) Here, hydrogen (H 2 ) is the reducing agent.
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Chemical Reactions and Equations Class 10 Extra Questions
Want more such Class 10 Science Chapter wise extra Question? Check out below:-
CBSE Class 10 Mind Maps Book For 2026 Board Exams
CBSE Class 10 Science NCERT Exemplar
How to Prepare for Chemical Reactions and Equations Class 10?
1. Start with the NCERT Textbook
The NCERT book is the main source for your board exam. It explains all the concepts clearly and simply.
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Read the chapter line by line and understand each topic.
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Focus on the definition of a chemical reaction and how to write and balance equations.
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Highlight key points and examples for later revision.
2. Make Simple Notes
Making your own notes helps in better understanding and revision.
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Write down important reactions, formulas, and types of chemical reactions.
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Keep the notes short and clear so you can revise them quickly.
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Use bullet points and headings for easy reading.
3. Use Flashcards for Quick Revision
Flashcards help you memorise important terms and reactions quickly.
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Make flashcards for element symbols, common compounds, and definitions.
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Revise them daily or during free time.
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Keep them handy for last-minute preparation.
4. Solve NCERT In-Text and Back Questions
Many exam questions are based directly on NCERT exercises.
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Practise all in-text and end-of-chapter questions.
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Write detailed answers to learn the proper format.
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Revisit any question you find difficult to understand.
5. Practise Extra Questions
Extra questions help you prepare for tricky and application-based problems.
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Solve extra questions from sample papers or free PDFs provided by PW and other trusted platforms.
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Focus on questions that ask for reaction types or balancing of equations.
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Write the answers in your notebook to improve writing practice.
Check Out: CBSE Class 10th Previous Year Papers
6. Use NCERT Solutions for Help
Solutions help when you are stuck or unsure about an answer.
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Refer to NCERT Solutions from reliable sources like PW.
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Try to understand the steps instead of simply copying the answers.
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Compare your written answers with these to find where you need improvement.
7. Understand Real-Life Examples
Linking the topic with real life helps in better understanding.
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Study examples like rusting, photosynthesis, and the reaction of quicklime with water.
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Think about where you see chemical changes happening around you.
8. Revise Regularly
Consistent revision keeps the concepts fresh in your mind.
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Set a weekly plan to revise the chapter.
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Go through your notes, flashcards, and important equations.
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Use weekends to test yourself with short quizzes.
9. Practise Sample Papers and Previous Year Questions
This will help you get familiar with the exam pattern and question types.
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Solve 2-3 sample papers to test your preparation.
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Focus on the previous year's questions related to this chapter.
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Time yourself while practising to improve your speed.
Read More: NCERT Solutions for Class 10 Science Chapter 1
Chemical Reactions and Equations FAQs
1. What is a chemical reaction?
A chemical reaction is a process in which one or more substances (reactants) are converted into new substances (products) with different properties.
2. How do you identify that a chemical reaction has taken place?
Some common signs include a change in colour, evolution of gas, formation of precipitate, a change in temperature, or change in state.
3. What is a balanced chemical equation?
A balanced chemical equation has an equal number of atoms of each element on both sides of the equation. This follows the Law of Conservation of Mass.
4. Why is it important to balance chemical equations?
Balancing ensures that the number of atoms of each element is the same on both sides of the equation, showing that mass is conserved during the reaction.
5. What is the difference between a physical and chemical change?
A physical change affects only the state or appearance, while a chemical change forms a new substance with different properties.
