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Class 10 Science question answer: all 13 NCERT chapters, with notes and practice

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In short: this page lists all 13 chapters of the NCERT Class 10 Science textbook (Reprint 2026-27) in the book's order, with the page each chapter starts on and our guides for it: questions with worked answers and revision notes for every chapter, and notes in Hindi for chapters 1 to 8. At the end are 8 quick questions, one idea each from eight chapters, to check yourself before you open a chapter guide.

The questions on this page and in the chapter guides are our own, drafted with AI help. Every answer was checked against the textbook pages named under it, but no practising teacher has reviewed them yet. If you find a mistake, please tell us.

All 13 chapters

The chapter titles and start pages are from the book's contents page (Science, Textbook for Class X, Reprint 2026-27). The book's answers section is on pages 218 and 219.

ChapterStarts on pageQuestions with answersNotes and explanations
1 Chemical Reactions and Equations1Questions with answersNotes, explained
2 Acids, Bases and Salts17Questions with answersNotes
3 Metals and Non-metals37Questions with answersNotes
4 Carbon and its Compounds58Questions with answersNotes, in Hindi
5 Life Processes79Questions with answersNotes, in Hindi
6 Control and Coordination100Questions with answersNotes, in Hindi
7 How do Organisms Reproduce?113Questions with answersNotes, in Hindi
8 Heredity128Questions with answersNotes, in Hindi
9 Light – Reflection and Refraction134Questions with answersNotes
10 The Human Eye and the Colourful World161Questions with answersNotes
11 Electricity171Questions with answers, numericalsNotes, explained
12 Magnetic Effects of Electric Current195Questions with answersNotes
13 Our Environment208Questions with answersNotes

In Hindi (chapters 4 to 8 are in the table above): Chapter 1, Chapter 2 and Chapter 3, notes and questions with answers.

How to use these guides

  1. Read the chapter in the textbook first, then the notes, then try the questions on paper before you open each answer.
  2. Mark the page. Every answer in our guides names the textbook page it comes from, so you can go back to the exact paragraph when you get one wrong.
  3. Check the marks. Which chapters carry the most marks, and how the board paper is laid out, are in our syllabus guide and sample paper guide.

8 quick questions to check yourself

Question 1 (Chapter 1). On standing, hydrogen peroxide slowly breaks down: 2H₂O₂ → 2H₂O + O₂. What type of reaction is this?

Answer: a decomposition reaction. A single reactant breaks down into simpler products, here water and oxygen. (Decomposition reactions, page 8.)

Question 2 (Chapter 4). Butane is C₄H₁₀, with only single bonds. How many covalent bonds are there in one molecule?

Answer: 13. The four carbon atoms form a chain with 3 carbon-carbon bonds, and each of the 10 hydrogen atoms is joined to a carbon by one bond: 3 + 10 = 13. Each carbon then has four bonds. (Butane in the table of saturated compounds, page 64; covalent bonds, page 60.)

Question 3 (Chapter 5). Which chamber of the human heart first receives the oxygen-rich blood coming back from the lungs?

Answer: the left atrium. From the left atrium the blood passes to the left ventricle, which pumps it to the rest of the body. (The heart, page 92.)

Question 4 (Chapter 8). Why does every child carry two versions of each trait?

Answer: because both parents, the father and the mother, pass on almost the same amount of genetic material to a child, so for each trait one version comes from each parent. (Rules for the inheritance of traits, page 129.)

Question 5 (Chapter 10). White light passes through a glass prism and splits into a band of colours. Which colour bends the least, and what is the order of the colours?

Answer: red bends the least; the order is violet, indigo, blue, green, yellow, orange, red (VIBGYOR). Violet bends the most, which is why it is at the other end of the band, the spectrum. (Dispersion by a prism, page 167.)

Question 6 (Chapter 11). Three resistors of 6 Ω each are joined in parallel. What is their equivalent resistance? What would it be if they were joined in series?

Answer: 2 Ω in parallel, 18 Ω in series. In parallel, 1/Rₚ = 1/6 + 1/6 + 1/6 = 3/6 = 1/2, so Rₚ = 2 Ω, less than the smallest resistor. In series the resistances simply add: 6 + 6 + 6 = 18 Ω. (Resistors in parallel, page 186.)

Question 7 (Chapter 12). A straight wire stands vertically, and the current in it flows upwards. Seen from above, do the magnetic field lines around it go clockwise or anticlockwise?

Answer: anticlockwise. By the right-hand thumb rule, point the thumb of your right hand along the current, upwards; your fingers then curl round the wire anticlockwise as seen from above. (Right-hand thumb rule, pages 199 and 200.)

Question 8 (Chapter 13). The plants in a food chain hold 20,000 J of food energy. About how much of it reaches the secondary consumers, two steps up?

Answer: about 200 J. On average about 10% passes from one level to the next: 10% of 20,000 J is 2,000 J for the primary consumers, and 10% of that is 200 J for the secondary consumers. This is why food chains generally have only three or four steps. (Flow of energy, page 210.)

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CMDLearn is building an AI tutor for Classes 1 to 10 that explains a step and checks the child's working, but leaves the writing to the child. It is still in development, and no child uses it yet. If you would like to hear when there is something to try, you can join the waitlist.

Sources

All opened and read on 4 November 2026. Page numbers are the printed page numbers of the textbook.

The chapter titles, page numbers and facts are from the textbook pages above. The questions and answers are our own, and every number was re-checked by script. This guide is general information; follow your teacher and the official CBSE notices.

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