CBSE Class 10 Science Important Questions | PDF Download for 2026-27

CBSE Class 10 Science Important Questions for the academic session 2026-27 are based on all the chapters included in the Class 10 Science NCERT textbook. These questions are based on the revised CBSE exam pattern and help students to prepare for the exam thoroughly. 

Some of the most important chapters for Science include Light, Electricity, Chemical Reactions and Equations are covered properly with different question types. Down below, there are few important questions given for reference so keep reading to find out.  

CBSE Class 10 Important Questions: Chapter-wise PDFs

Instead of going through the entire book for finding questions to practice, students can go through these links of chapter-wsie important questions for Science Class 10.  These questions are completely based on CBSE Syllabus for Class 10. 

Chapter 1: Chemical Reactions and Equations Important Questions

Chapter 2: Acids, Bases and Salts Important Questions

Chapter 3: Metals and Non-metals Important Questions

Chapter 4: Carbon and its Compounds Important Questions

Chapter 5: Life Processes Important Questions

Chapter 6: Control and Coordination Important Questions

Chapter 7: How do Organisms Reproduce? Important Questions

Chapter 8: Heredity Important Questions

Chapter 9: Light - Reflection and Refraction Important Questions

Chapter 10: The Human Eye and the Colourful World Important Questions

Chapter 1: Electricity Important Questions

Chapter 12: Magnetic Effects of Electric Current Important Questions

Chapter 13: Our Environment Important Questions

CBSE Class 10 Science Exam Pattern: At a Glance

The table below shows Science exam pattern for Class 10 at a glance: 

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Class 10 Science Important Questions for 2026-27 - With Solutions

This section includes some chapter-wise important questions for Science Class 10 with a proper solution to help students know better about them.

1. Chemical Reactions and Equations

Q1. (Easy) What is a chemical equation?

Ans: A chemical equation is a symbolic representation of a chemical reaction using the formulae of reactants and products.

• Reactants are written on the left side
• Products are written on the right side. 

It shows the transformation of substances during a chemical reaction in a short and balanced form.

Q2. (Easy) Balance the equation: Fe + H₂O - Fe₃O₄ + H₂

Ans: Balanced equation is: 3Fe + 4H₂O - Fe₃O₄ + 4H₂

• First, iron atoms are balanced by putting 3 before Fe
• Then hydrogen and oxygen atoms are balanced using coefficients
• Final equation has equal number of atoms on both sides

Q3. (Medium) What is oxidation and reduction? Give an example.

Ans: Oxidation is the process of addition of oxygen or removal of hydrogen and reduction is the process of removal of oxygen or addition of hydrogen

Example: CuO + H₂ - Cu + H₂O

• CuO is reduced to Cu (removal of oxygen)
• H₂ is oxidized to H₂O (addition of oxygen)

Q4. (HOTS) Why do silver articles turn black on exposure to air?

Ans: Silver articles turn black due to the formation of a layer of silver sulphide (Ag₂S). Silver reacts with sulfur compounds present in air. This is a slow oxidation reaction. The black coating reduces the shine of silver objects

2. Acids, Bases and Salts

Q1. (Easy) What happens when an acid reacts with a base?

Ans: When an acid reacts with a base, a neutralization reaction takes place.

• Acid + Base - Salt + Water
• This reaction releases heat energy
• The resulting solution becomes less acidic or less basic depending on quantities

Q2. (Medium) Why does dry HCl gas not change the color of dry litmus paper?

Ans: Dry HCl gas does not show acidic behavior because:

• Acids show properties only in aqueous solution
• HCl requires water to release H⁺ ions
• Without water, no ion formation occurs, so litmus remains unchanged

Q3. (Medium) What is the pH scale? Explain its importance.

Ans: The pH scale measures the acidity or basicity of a solution on a scale of 0 to 14.

• pH < 7 - acidic solution
• pH = 7 - neutral solution
• pH > 7 - basic solution
  It is important because it helps determine strength of acids and bases in daily life like soil, digestion and water quality.

Q4. (HOTS) Why is toothpaste basic in nature?

Ans: Toothpaste is basic because it neutralizes acids produced by bacteria in the mouth. These acids can damage tooth enamel. Basic nature helps prevent tooth decay and maintains oral hygiene

3. Metals and Non-metals

Q1. (Easy) Why are metals good conductors of electricity?

Ans: Metals are good conductors because they contain free electrons. These electrons move freely through the metal structure and this movement allows electric current to pass easily.

Q2. (Medium) What is rusting of iron?

Ans: Rusting is the corrosion of iron when it reacts with oxygen and moisture. Iron forms hydrated iron oxide (Fe₂O₃·xH₂O). Rust appears as a reddish-brown layer. It weakens the metal over time

Q3. (Medium) Why are ionic compounds brittle?

Ans: Ionic compounds are brittle because:

• They have strong electrostatic forces between ions
• When force is applied, layers shift
• Similar charges come closer and repel each other, causing the compound to break

Q4. (HOTS) Why is sodium stored in kerosene?

Ans: Sodium is stored in kerosene because:

• It reacts violently with air and water
• It can catch fire spontaneously
• Kerosene prevents contact with air and moisture

4. Carbon and its Compounds

Q1. (Easy) What is catenation?

Ans: Catenation is the ability of carbon atoms to form long chains by bonding with other carbon atoms. This property is unique due to strong carbon-carbon bonds. It leads to formation of large organic compounds

Q2. (Medium) Why does carbon form covalent bonds?

Ans: Carbon forms covalent bonds because:

• It has 4 valence electrons
• It cannot easily lose or gain electrons
• It shares electrons to achieve stable configuration

Q3. (Medium) What is a functional group?

Ans: A functional group is an atom or group of atoms that determines the chemical properties of an organic compound. Examples: Alcohol group (-OH) and carboxylic acid group (-COOH)

Q4. (HOTS) Why are hydrocarbons used as fuels?

Ans: Hydrocarbons are used as fuels because:

• They burn easily in oxygen
• They release large amounts of heat energy
• They produce carbon dioxide and water as products

5. Life Processes

Q1. (Easy) What is nutrition?

Ans: Nutrition is the process by which organisms obtain food and use it for energy, growth and repair. It provides essential nutrients and supports all life activities.

Q2. (Medium) What is the function of stomata?

Ans: Stomata are tiny pores on leaves that allow exchange of gases like CO₂ and O₂. It also helps in transpiration (loss of water vapor).

Q3. (Medium) Why is respiration important?

Ans: Respiration is important because:

• It releases energy from food
• This energy is used for growth, movement and repair
• It is a continuous process in living organisms

Q4. (HOTS) Why is double circulation important in humans?

Ans: Double circulation is important because it keeps oxygenated and deoxygenated blood separate. It ensures efficient oxygen supply to body cells and supports high energy demand in humans

6. Control and Coordination

Q1. (Easy) What is the function of neurons?

Ans: Neurons are nerve cells that:

• Transmit electrical impulses
• Carry messages between brain and body
• Help in coordination of body activities

Q2. (Medium) What is reflex action?

Ans: Reflex action is an automatic response to a stimulus without conscious thinking. It is controlled by the spinal cord and it helps protect the body from harm.

Q3. (HOTS) Why do plants bend towards light?

Ans: Plants bend towards light due to phototropism:

• Auxin hormone moves to shaded side
• Cells grow faster on shaded side
• This causes bending towards light

7. How do Organisms Reproduce?

Q1. (Easy) What is reproduction?

Ans: Reproduction is the biological process by which organisms produce new individuals of the same species. It ensures continuity of life and helps maintain population.

Q2. (Medium) What is binary fission?

Ans: Binary fission is a type of asexual reproduction in which one cell divides into two identical daughter cells. It occurs in unicellular organisms like Amoeba

Q3. (HOTS) Why is variation important in reproduction?

Ans: Variation is important because:

• It helps organisms adapt to environmental changes
• Increases chances of survival
• Prevents extinction of species

8. Heredity

Q1. (Easy) What is heredity?

Ans: Heredity is the transfer of traits from parents to offspring.

• It explains similarities between generations
• Controlled by genes

Q2. (Medium) What are genes?

Ans: Genes are units of heredity located on chromosomes. They control specific traits like eye color, height and are passed from parents to offspring

Q3. (HOTS) Why are offspring not identical to parents?

Ans: Offspring are not identical because:

• Genetic recombination occurs during reproduction
• Variation is introduced during gene inheritance
• Environment also influences traits

9. Light - Reflection and Refraction

Q1. (Easy) What is reflection of light?

Ans: Reflection is the bouncing back of light when it strikes a surface.

• It follows laws of reflection
• It helps us see objects

Q2. (Medium) State laws of reflection.

Ans: Laws of reflection are:

• Angle of incidence = Angle of reflection
• Incident ray, reflected ray and normal lie in the same plane

Q3. (HOTS) Why does a straw look bent in water?

Ans: This happens due to refraction:

• Light changes direction when moving from water to air
• This creates a shifted image
• Hence straw appears bent

10. Human Eye and Colourful World

Q1. (Easy) What is myopia?

Ans: Myopia is a defect of vision in which:

• Nearby objects are seen clearly
• Distant objects appear blurred
• It is corrected using concave lenses

Q2. (Medium) Why is the sky blue?

Ans: The sky appears blue due to scattering of light:

• Shorter wavelengths (blue light) scatter more
• This scattered light reaches our eyes

Q3. (HOTS) Why do stars twinkle?

Ans: Stars twinkle because:

• Their light passes through different atmospheric layers
• Refraction keeps changing
• This causes apparent fluctuation in brightness

11. Electricity

Q1. (Easy) What is electric current?

Ans: Electric current is the flow of electric charge through a conductor. It is measured in amperes and requires a potential difference

Q2. (Medium) State Ohm’s Law.

Ans:
Ohm’s Law states that:

• V ∝ I (at constant temperature)
• V = IR, where R is resistance

Q3. (HOTS) Why do electric wires heat up?

Ans: Electric wires heat due to:

• Resistance offered to current
• Electrical energy converting into heat energy
• This is called Joule heating effect

12. Magnetic Effects of Electric Current

Q1. (Easy) What is a magnetic field?

Ans: A magnetic field is the region around a magnet where magnetic force can be experienced.

• It has direction and strength
• Represented by field lines

Q2. (Medium) What is an electromagnet?

Ans: An electromagnet is a temporary magnet:

• Made by passing current through a coil
• Strength can be controlled
• Used in cranes and devices

Q3. (HOTS) Why is soft iron used in electromagnets?

Ans: Soft iron is used because:

• It gets magnetized easily
• It loses magnetism quickly when current stops
• Makes electromagnet efficient

13. Our Environment

Q1. (Easy) What is an ecosystem?

Ans: An ecosystem is a system where:

• Living organisms interact with each other
• And with their physical environment
• It includes biotic and abiotic components

Q2. (Medium) What is a food chain?

Ans: A food chain is a sequence showing:

• Transfer of energy from one organism to another
• Example: Grass - Deer - Lion

Q3. (HOTS) Why is energy flow unidirectional?

Ans: Energy flow is unidirectional because:

• Energy is lost as heat at each trophic level
• It cannot be recycled back
• Hence it flows in one direction only

Chapter Weightage Analysis - Class 10 Science

Here, clear unit and chapter-wise weightage breakdown is given for CBSE Class 10 Science.

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Most Important Chapters for CBSE Class 10 Science 

As per the analysis of the CBSE board pattern for Science, some topics are continuously on high weightage and require stronger conceptual clarity. These chapters should be prioritized when practicing. 

Highest Weightage Chapters

1. Electricity

• Trend (Last 5 years): Very high repetition (numericals and theory every year)
• Expected Questions: Ohm’s Law numericals, resistance combinations, circuit diagrams
• Focus Area: Stepwise numericals and derivations
• Skip Risk: Students often ignore numericals  but they are guaranteed marks scorers

2. Light - Reflection and Refraction

• Trend: Consistently high weightage in Physics section
• Expected Questions: Ray diagrams, lens formula, mirror formula applications
• Focus Area: Diagram-based and numerical problem solving
• Skip Risk: Ray diagrams (very frequently asked but often ignored)

3. Life Processes

• Trend: 1-2 long questions every year
• Expected Questions: Human digestion, respiration, transport in plants
• Focus Area: Flow charts and labelled diagrams
• Skip Risk: Students often memorize instead of understanding processes

4. Chemical Reactions and Equations

• Trend: Always included in MCQ and short answers
• Expected Questions: Balancing equations, oxidation-reduction, reaction types
• Focus Area: Equation balancing
• Skip Risk: Redox reactions are often underprepared

Moderate Weightage Chapters

5. Acids, Bases and Salts

• Frequent MCQs and application-based questions
• Expected: pH scale, salts, neutralization reactions

6. Metals and Non-metals

• Expected: corrosion, reactivity series, ionic bonding

7. Carbon and its Compounds

• Expected: functional groups, ethanol/ethanoic acid reactions

8. Control and Coordination

• Expected: hormones, nervous system, reflex action diagrams

9. Heredity

• Moderate difficulty, concept-based
• Expected: Mendel laws, traits inheritance

10. How do Organisms Reproduce?

• Appears in case-based questions
• Expected: sexual vs asexual reproduction

Lower Weightage but High Scoring Chapters

11. Our Environment

• Very short chapter but direct questions every year
• Expected: food chains, ecological pyramids, waste management

12. Human Eye and Colourful World

• Short but conceptually tricky
• Expected: defects of vision, dispersion, scattering

Chapters Commonly Skipped  but Should Not Be 

Students often ignore these due to less  weightage, but CBSE often includes direct questions from them:

• Our Environment - easy 3-5 marks guaranteed
• Human Eye and Colourful World - diagram & concept questions
• Control and Coordination - short but scoring
• Heredity - conceptual MCQs in every paper

Final Exam Insight

• Physics carries the highest numerical weightage (Electricity and Light combined)
• Chemistry is mostly reaction-based and application questions
• Biology is theory-heavy but very scoring with diagrams
• Short chapters scores the easiest marks

Score Better Using Class 10 Science Important Questions

The step-by-step plan to approach the important questions can be very helpful for students to achieve better scores in Class 10 Science  exams. 

Step 1: Complete NCERT First: Before starting with anything else, it is important to complete understanding and practice from NCERT Science textbook first as that will form the base to anything else. 

Step 2: Solve chapter-wise important questions: Next, start with practicing important questions of the chapters with highest weightage. Retention of the concepts from these chapters will complete a big chunk of the syllabus.

Step 3: Practice mixed question formats every weekend: Keep weekends clear for practice only. Practice mixed important questions for all the chapters to develop exam readiness. 

Step 4: Track weak areas and mistakes: While practicing, mark questions which feel difficult so that during revision, you can get back to them and know what mistakes should be avoided in the exam. 

Scoring Strategies for Class 10 Science Exam 

Using these strategies along with the way of using Science, important questions can help score better in CBSE Science Board exam Class 10. These strategies will improve accuracy and maximise marks. 

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• Draw neat, labelled diagrams: Use neat labelled diagrams in chapters like Life Processes, Light, Human Eye and Magnetic Effects of Electric Current wherever seems important and required. 

• Show every step in numericals: In Physics, whenever a numerical question comes up, show every step of reaching the final answer. 
• Revise NCERT definitions and key terms: Many MCQs and short answers are based on key terms and definitions given in the NCERT textbook in bubble or in between the text. It is important to go through definitions like this properly. 
• Write answers in points: Do not write the entire answer in paragraphs. Add bullet points, heading, paragraphs and diagrams to make the answer look more presentable and easy to read and score. 

FAQs

Q1. What types of questions are asked in Class 10 Science 2026-27?

Ans. Class 10 Science 2026-27 includes MCQs, short answer questions, long answer questions, case-based questions and HOTS.

Q2. Which chapters carry the highest marks in Class 10 Science?

Ans. Chapters like Electricity, Light - Reflection and Refraction and Life Processes usually carry higher weightage. Chemical Reactions and Carbon and its Compounds are also frequently asked in both MCQs and long answers. 

Q3. Is NCERT enough for Class 10 Science or should I solve extra questions?

Ans. NCERT is the most important source for Class 10 Science because most board questions are directly based on it. However, solving important questions and sample papers improves application skills and exam readiness. 

Q4. How many important questions should I practise per chapter?

Ans. Students should practise at least 10-15 important questions per chapter depending on its weightage. High-scoring chapters like Electricity and Life Processes require more practice. 

Q5. What are HOTS questions in Class 10 Science?

Ans. HOTS (Higher Order Thinking Skills) questions test application and reasoning ability instead of direct memory-based answers. These questions often require explanation, analysis or real-life application of concepts.

Q6. Are case-based questions included in Class 10 Science 2026-27?

Ans. Yes, case-based questions are an important part of the CBSE Class 10 Science exam pattern. These questions are usually based on real-life scenarios linked to NCERT concepts. 

Q7. How can I download the Class 10 Science important questions PDF 2027?

Ans. The Class 10 Science important questions PDF can be downloaded directly from the chapter-wise section of the page. Students can use it for offline practice and revision.

Q8. Will diagram-based questions be asked in Class 10 board exam 2027?

Ans. Yes, diagram-based questions are commonly asked in Biology and Physics sections. Proper labelling and neat presentation can help secure full marks.

Q9. What is the best time to start solving important questions for boards?

Ans. Students should start solving important questions after completing their first NCERT reading of each chapter. Ideally, regular practice should begin months before the board exam.