CBSE Class 10 Science Important Questions 2027 - Chapter Wise

In short: CBSE Class 10 Science 2027 focuses on Chemistry (25 marks), Biology (25 marks), and Physics (25 marks) in the theory paper. The most repeated questions come from Chemical Reactions, Life Processes, Electricity, and Light. This guide lists the chapter-wise important questions based on past year patterns so you know exactly what to focus on.

CBSE Class 10 Science carries 80 marks in theory. The paper covers Physics, Chemistry, and Biology in one 3-hour exam. Knowing which chapters carry the most marks and which question types repeat every year gives you a clear edge.

This guide breaks down the most important questions from each section based on the 2027 exam pattern.

Mark Distribution by Unit

Key insight: Chemistry (25 marks) and Biology (25 marks) together carry 50 out of 80 marks. Physics carries 25 marks. Environment carries only 5 marks. For a detailed breakdown, see our CBSE Class 10 Science chapter-wise marks weightage guide.

Chemistry: Most Important Questions

Chapter 1: Chemical Reactions and Equations

This chapter is the foundation. Questions appear in every section of the paper.

• Write balanced chemical equations for: (a) burning of magnesium ribbon, (b) reaction of zinc with dilute sulphuric acid, (c) decomposition of ferrous sulphate. (3 marks — asked almost every year)
• What is a combination reaction? Give an example. (2 marks)
• What are the differences between exothermic and endothermic reactions? Give two examples of each. (3 marks)
• What is rancidity? How can it be prevented? (2 marks)

Tip: Balancing equations is a guaranteed question. Practice at least 20 different equations.

Chapter 2: Acids, Bases, and Salts

• What happens when an acid reacts with a metal? Write the general equation and give one example. (2 marks)
• How is Plaster of Paris prepared? Write the chemical equation. (3 marks)
• What is a pH scale? What happens to the pH of a solution when you add an acid to it? (2 marks)
• Why does dry HCl gas not show acidic behavior? (1 mark MCQ — very frequently asked)

Chapter 3: Metals and Non-Metals

• What is the reactivity series? Arrange the following metals in decreasing order of reactivity: Cu, Fe, Zn, Na, Au. (2 marks)
• Explain the extraction of metals of medium reactivity from their sulphide ores. (5 marks)
• What is corrosion? How can iron be protected from corrosion? (3 marks)
• Why are ionic compounds generally solid at room temperature? (1 mark)

Chapter 4: Carbon and Its Compounds

• What is a homologous series? Give any two characteristics. (2 marks)
• Draw the structure of ethanol and ethanoic acid. (2 marks)
• What are the differences between soap and detergent? (3 marks)
• Write the chemical equation for the saponification reaction. (2 marks)

Biology: Most Important Questions

Chapter 6: Life Processes

This chapter alone carries 8-10 marks typically.

• Draw a well-labeled diagram of the human digestive system. (5 marks)
• Describe the process of nutrition in Amoeba. (3 marks)
• What is the role of saliva in the digestion of food? (2 marks)
• Explain the mechanism of breathing in human beings. (3 marks)
• Draw a diagram of the human heart and label: left ventricle, right atrium, aorta, pulmonary artery. (3 marks)

Tip: The digestive system and heart diagrams are asked in alternate years. Learn both perfectly.

Chapter 7: Control and Coordination

• What is the difference between a reflex action and walking? (2 marks)
• Draw a labeled diagram of a neuron. (3 marks)
• What are plant hormones? Name any two and state their functions. (3 marks)

Chapter 8: How Do Organisms Reproduce?

• What are the advantages of vegetative propagation? (2 marks)
• Draw a well-labeled diagram of the longitudinal section of a flower. (3 marks)
• What is the significance of DNA copying in reproduction? (3 marks)

Physics: Most Important Questions

Chapter 10: Light - Reflection and Refraction

• State Snell's law of refraction. A light ray passes from air to glass. If the angle of incidence is 45 degrees and the refractive index of glass is 1.5, find the angle of refraction. (3 marks)
• An object is placed at 15 cm from a convex mirror of focal length 10 cm. Find the position, nature, and size of the image. (3 marks)
• Draw a ray diagram to show the image formed when an object is placed between the focus and centre of curvature of a concave mirror. (2 marks)

Tip: Mirror formula and lens formula numericals carry 3-5 marks. Practice at least 10 numericals from each.

Chapter 12: Electricity

• State Ohm's law. Draw the circuit diagram used to verify it. (3 marks)
• Three resistors of 2 ohm, 3 ohm, and 6 ohm are connected in parallel. Find the equivalent resistance. (3 marks)
• What is the difference between resistance and resistivity? (2 marks)
• An electric heater of resistance 8 ohm draws 15 A from the supply. Calculate the rate at which energy is dissipated. (2 marks)

Chapter 13: Magnetic Effects of Electric Current

• What is electromagnetic induction? State Faraday's law. (3 marks)
• Draw the pattern of magnetic field lines around a current-carrying solenoid. (2 marks)
• What is the function of a fuse in an electric circuit? (1 mark)

Scoring Strategy for Science

1. Do the MCQ section first (20 marks in 15-20 minutes). These test direct recall.
2. Biology questions next — draw neat, labeled diagrams. Diagrams carry 2-3 marks each and are the easiest marks in the paper.
3. Chemistry equations — always balance. An unbalanced equation gets zero marks.
4. Physics numericals last — these take the most time. Show every step and include units.
5. Never leave the Environment chapter — it is only 5 marks but the questions are very simple. Free marks.

For a complete approach to scoring well across all subjects, check out how to score 90% in CBSE Class 10. Also, make sure you know how to write answers in board exams to convert your knowledge into maximum marks.

Frequently Asked Questions

How many chapters are important for CBSE Class 10 Science 2027?

All chapters are part of the syllabus, but some carry significantly more marks. Chemical Reactions, Life Processes, Electricity, and Light together account for roughly 40 to 45 marks out of 80. Focus on these four chapters first, then cover the rest.

Should I study from NCERT only for Science board exam?

NCERT is your primary resource and most board questions come directly from it. However, for Physics and Chemistry numericals, practicing from sample papers and previous year papers gives you exposure to different question formats. Use CBSE sample papers effectively to supplement your NCERT preparation.

How do I prepare for diagram-based questions in Science?

Biology and Physics both have diagram-heavy questions worth 2 to 5 marks. Practice drawing diagrams from memory at least 3 to 4 times. Label neatly with straight lines, and always include a title. The human heart, digestive system, neuron, ray diagrams, and electric circuits are the most frequently asked diagrams.

What is the best revision strategy for Science before the exam?

Start with formulas and diagrams, then move to reaction equations and definitions. Solve at least 5 previous year papers under timed conditions. For a detailed plan, read our best revision strategy before board exams.

Are case-based questions asked in CBSE Science 2027?

Yes, Section D has case-based or source-based questions worth 4 marks each. These questions test your understanding of a concept applied to a real-world scenario. Practice them from sample papers to get familiar with the format.

Practice on Padhaao

Every CBSE Class 10 Science chapter is available with solved examples, board-exam style questions, and 10 different learning modes.

• Quiz mode: 10 MCQs per topic for Section A practice
• Exam Practice: Board-style paper with model answers
• Important Questions: Most likely board exam questions with marks distribution

3 free chapters every day.