CBSE Class 10 Science Most Repeated Board Questions: Science is an important subject for Class 10 students, especially for those preparing for the 2025 Board Exam. Knowing the CBSE Class 10 Science Frequently Asked Questions helps students focus on important topics and score higher marks. These questions have appeared many times in previous exams, which means they have a higher chance of being asked again. By practising these questions, students can improve their speed, accuracy, and time management during the exam. It also boosts their confidence, reduces exam stress, and makes revision easier. To help students prepare better, we have compiled a CBSE Class 10 Science Chapter-wise Board Questions from past CBSE board exams. A downloadable PDF is also available for a more organised and effective revision plan.
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CBSE Class 10 Complete Study Material For All Subjects
Importance of Practising CBSE Class 10 Science Most Repeated Questions
The Class 10 Board Exams are an important stage in every student’s academic journey, and scoring well requires smart preparation. One of the best ways to improve performance is by practising the most repeated questions from previous years. These questions give a clear idea of the exam pattern, key topics, and difficulty level. They also help students understand common question types, improve speed and accuracy, and manage time better. Practising these questions highlights high-weightage topics, strengthens problem-solving skills, and reduces exam stress- boosting confidence and chances of scoring higher.
- Helps in understanding the overall difficulty level of the exam.
- Familiarises students with commonly asked question types in board exams.
- Improves speed, accuracy, and time management skills.
- Highlights high-weightage topics essential for scoring well.
- Enhances problem-solving skills while reducing exam-related stress.
CBSE Class 10 Science Chapter-wise Board Questions
Preparing for the CBSE Class 10 Science Board Exam becomes much easier when you know which questions are asked most frequently. Chapter-wise most repeated Science questions help students focus on key topics and study smartly. Practising these questions improves speed, accuracy, and confidence. This list of Class 10 Science Chapter-wise Most Repeated Questions is created to help you revise better and score higher marks in the exam.
CBSE Class 10 Acids, Bases and Salts Board Questions
Q1. Acetic acid solution turns: (CBSE Board Paper 2011)
(1) blue litmus red
(2) red litmus blue
(3) blue litmus colourless
(4) red litmus colourless
Q2. What do you observe when you drop a few drops of acetic acid to test tubes containing (CBSE Board Paper 2016)
(a) phenolphthalein
(b) distilled water
(c) universal indicator
(d) sodium hydrogen carbonate powder
Q3. 2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves, which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with a dilute solution of a strong acid.
OR
The pH of a salt used to make tasty and crispy pakoras is 14. Identify the salt and write a chemical equation for its formation. List its two uses. (CBSE Board Paper 2018)
Q4. Identify the acid and the base from which sodium chloride is obtained. Which type of salt is it? When is it called rock salt? How is rock salt formed? (CBSE Board Paper 2019)
Q5. (i) Suggest a safe procedure of diluting a strong concentrated acid.
(ii) Name the salt formed when sulphuric acid is added to sodium hydroxide and write its pH.
(iii) Dry HCl gas does not change the colour of dry blue litmus paper. Why? (CBSE Board Paper 2023)
CBSE Class 10 Carbon and Its Compounds Board Questions
Q1. Acetic acid smells like: (CBSE Board Paper 2011)
(1) a banana
(2) vinegar
(3) an orange
(4) a lemon
Q2. (a) Give a chemical test to distinguish between saturated and unsaturated hydrocarbons.
(b) Name the products formed when ethane burns in the air. Write a balanced chemical equation for the reaction showing the types of energies liberated.
(c) Why is the reaction between methane and chlorine in the presence of sunlight considered a substitution reaction? (CBSE Board Paper 2016)
Q3. (a) Why are most carbon compounds poor conductors of electricity?
(b) Write the name and structure of a saturated compound in which the carbon atoms are arranged in a ring. Give the number of single bonds present in this compound. (CBSE Board Paper 2018)
Q4. In three test tubes A, B, and C, three different liquids namely, distilled water, underground water and distilled water in which a pinch of calcium sulphate is dissolved, respectively are taken. Equal amount of soap solution is added to each test tube and the contents are shaken. In which test tube will the length of the foam (lather) be longest? Justify your answer. (CBSE Board Paper 2019)
Q5. Write the chemical equation for the following :
(i) Combustion of methane
(ii) Oxidation of ethanol
(iii) Hydrogenation of ethene
(iv) Esterification Reaction
(v) Saponification Reaction (CBSE Board Paper 2023)
CBSE Class 10 Chemical Reactions and Equations Board Questions
Q1. In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution:
(A) exchange of atoms takes place
(B) exchange of ions takes place
(C) a precipitate is produced
(D) an insoluble salt is produced
The correct option is: (CBSE Board Paper 2020)
(a) (B) and (D)
(b) (A) and (C)
(c) only (B)
(d) (B), (C) and (D)
Q2. The question consists of two statements- Assertion (A) and Reason (R).
Assertion (A): Burning of Natural gas is an endothermic process.
Reason (R): Methane gas combines with oxygen to produce carbon dioxide and water.
Select the appropriate option given below: (CBSE Board Paper 2021)
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
Q3. (i) While electrolysing water before passing the current some drops of an acid are added. Why? Name the gases liberated at cathode and anode. Write the relationship between the volume of gas collected at anode and the volume of gas collected at cathode.
(ii) What is observed when silver chloride is exposed to sunlight? Give the type of reaction involved. (CBSE Board Paper 2018)
Q4. To show that zinc is a more active metal than copper, the correct procedure is to: (CBSE Board Paper 2011)
(1) add dilute nitric acid on strips of both the metals.
(2) observe transmission of heat through strips of zinc and copper.
(3) prepare solution of zinc sulphate and hang strip of copper into it.
(4) prepare solution of copper sulphate and hang strip of zinc into it.
Q5. Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity. (CBSE Board Paper 2023)
CBSE Class 10 Control and Coordination Board Questions
Q1. What are plant hormones? Name the plant hormones responsible for the following:
(i) Growth of stem
(ii) Promotion of cell division
(iii) Inhibition of growth
(iv) Elongation of cells (CBSE Board Paper 2019)
Q2. In plants, the role of cytokinin is: (CBSE Board Paper 2023)
(a) Promote cell division.
(b) Wilting of leaves.
(c) Promote the opening of stomatal pore.
(d) Help in the growth of stem.
Q3. What is feedback mechanism of hormonic regulation. Take the example of insulin to explain this phenomenon. (CBSE Board Paper 2019)
Q4. Name the hormones secreted by the following endocrine glands and specify one function of each:
(a) Thyroid
(b) Pituitary
(c) Pancreas (CBSE Board Paper 2018)
Q5. What is phototropism? Describe an activity to demonstrate phototropism. (CBSE Board Paper 2010)
CBSE Class 10 Electricity Board Questions
Q1. (a) List the factors on which the resistance of a conductor in the shape of a wire depends.
(b) Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason?
(c) Why are alloys commonly used in electrical heating devices? Give reason. (CBSE Board Paper 2018)
Q2. While studying the dependence of potential difference (V) across a resistor on the current (I) passing through it, in order to determine the resistance of the resistor, a student took 5 readings for different values of current and plotted a graph between V and I. He got a straight line graph
passing through the origin. What does the straight line signify? Write the method of determining the resistance of the resister using this graph.
OR
What would you suggest to a student if while performing an experiment he finds that the pointer/needle of the ammeter and voltmeter do not coincide with the zero marks on the scales when the circuit is open? No extra ammeter/voltmeter is available in the laboratory. (CBSE Board Paper 2019)
Q3. At the time of short circuit, the electric current in the circuit: (CBSE Board Paper 2020)
(a) vary continuously
(b) does not change
(c) reduces substantially
(d) increases heavily
Q4. (a) Write the mathematical expression for Joule's law of heating,
(b) Compute the heat generated while transferring 96000 coulomb of charge in two hours through a potential difference of 40 V. (CBSE Board Paper 2020)
Q5. (a) What is the heating effect of electric current?
(b) Write an expression for the amount of heat produced in a resistor when an electric current is passed through it stating the meanings of the symbols used.
(c) Name two appliances based on heating effect of electric current. (CBSE Board Paper 2022)
CBSE Class 10 Heredity and Evolution Board Questions
Q1. Explain Mendel’s law of independent inheritance. Give one example. (CBSE Board Paper 2011)
Q2. (a) Mendel crossed tall pea plants with dwarf pea plants in his experiment. Write his observations giving reason on the F1 and F2 generations.
(b) List any two contrasting characters other than height that Mendel used in his experiments in pea plants. (CBSE Board Paper 2014)
Q3. (a) What is genetics?
(b) What are genes? Where are the genes located? (CBSE Board Paper 2020)
Q4. A green stemmed tomato plant denoted by (GG) is crossed with a tomato plant with purple stem denoted by (gg).
(i) What colour of the stem would you expect in their F1 progeny?
(ii) In what ratio would you find the green and purple coloured stem in plants of F2 progeny?
(iii) What conclusion can be drawn for the above observations? (CBSE Board Paper 2022)
Q5. Which one of the given statements is incorrect: (CBSE Board Paper 2023)
(a) DNA has the complete information for a particular characteristic.
(b) DNA is the molecule responsible for the inheritance of characters from parents to offsprings.
(c) Change in information will produce a different protein.
(d) Characteristics will remain the same even if protein changes.
CBSE Class 10 How Do Organisms Reproduce Board Questions
Q1. List any two differences between pollination and fertilisation. (CBSE Board Paper 2010)
Q2. Write any two differences between binary fission and multiple fission in a tabular form as observed in cells of organisms. (CBSE Board Paper 2011)
Q3. (a) List two sexually transmitted diseases in each of the following cases:
(i) Bacterial infections
(ii) Viral infections
(b) How may the spread of such diseases be prevented? (CBSE Board Paper 2011)
Q4. During adolescence, the reproductive phase starts and (CBSE Board Paper 2023)
(a) general growth rate begins to slow down
(b) height becomes less
(c) the body weight is reduced
(d) hair growth decreases
Q5. (a) Name the two types of gametes produced by men.
(b) Does a male child inherit X chromosome from his father? Justify.
(c) How many types of gametes are produced by a human female? (CBSE Board Paper 2022)
CBSE Class 10 Life Processes Board Questions
Q1. (a) Mention any two components of blood.
(b) Trace the movement of oxygenated blood in the body.
(c) Write the function of valves present in between atria and ventricles.
(d) Write one structural difference between the composition of artery and veins.
OR
(a) Define excretion.
(b) Name the basic filtration unit present in the kidney.
(c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions :
(i) form urine.
(ii) is a long tube which collects urine from kidney.
(iii) store urine until it is passed out. (CBSE Board Paper 2018)
Q2. Write two different ways in which glucose is oxidized to provide energy in human body. Write the products formed in each case. (CBSE Board Paper 2019)
Q3. (a) Why is there a difference in the rate of breathing between aquatic organisms and terrestrial organisms? Explain.
(b) Draw a diagram of human respiratory system and label - pharynx, trachea, lungs, diaphragm and alveolar sac on it. (CBSE Board Paper 2020)
Q4. In living organisms during respiration which of the following products are not formed if oxygen is not available? (CBSE Board Paper 2021)
(a) Carbon dioxide + Water
(b) Carbon dioxide + Alcohol
(c) Lactic acid + Alcohol
(d) Carbon dioxide + Lactic Acid
Q5. (i) Name and explain the two modes of asexual reproduction observed in Hydra.
(ii) What is vegetative propagation? List two advantages of using this technique. (CBSE Board Paper 2023)
CBSE Class 10 Light - Reflection and Refraction Board Questions
Q1. Mention the types of mirrors used as (i) rear view mirrors, (ii) shaving mirrors. List two reasons to justify your answers in each case. (CBSE Board Paper 2013)
Q2. An object of height 6 cm is placed perpendicular to the principal axis of a lens of focal length 5 cm. Use lens formula to determine the position, size and nature of the image if the distance of the object from the lens is 10cm. (CBSE Board Paper 2013)
Q3. A student wants to project the image of a candle flame on the walls of the school laboratory by using a mirror.
(a) Which type of mirror should he use and why?
(b) At what distance, in terms of focal length 'f' of the mirror, should he place the candle flame to get the magnified image on the wall?
(c) Draw a ray diagram to show the formation of the image in this case.
(d) Can he use this mirror to project a diminished image of the candle flame on the same wall? State 'how' if your answer is 'yes' and 'why not' if your answer is 'no.' (CBSE Board Paper 2014)
Q4. List two differences in the characteristic properties of the virtual images formed by the two types of spherical lenses (concave and convex). How are these characteristics of the two lenses used in the correction of the two common defects of vision namely myopia and hypermetropia? (CBSE Board Paper 2023)
Q5. The radius of curvature of a converging mirror is 30 cm. At what distance from the mirror should an object be placed so as to obtain a virtual image? (CBSE Board Paper 2021)
(a) Infinity
(b) 30 cm
(c) Between 15 cm and 30 cm
(d) Between 0 cm and 15 cm
CBSE Class 10 Magnetic Effects of Electric Current Board Questions
Q1. What is a solenoid? Draw the pattern of magnetic field lines of a solenoid through which a steady current flows. What does the pattern of field lines inside the solenoid indicate? (CBSE Board Paper 2010)
Q2. (a) State Fleming's left hand rule.
(b) Write the' principle of working of an electric motor.
(c) Explain the function of the following parts of an electric motor.
(i) Armature (ii) Brushes (iii) Split ring (CBSE Board Paper 2018)
Q3. (a) Explain with the help of the pattern of magnetic field lines the distribution of magnetic field due to a current carrying a circular loop.
(b) Why is it that the magnetic field of a current carrying coil having n turns, is 'n' times as large as that produced by a single turn (loop)? (CBSE Board Paper 2020)
Q4. Assertion (A): A current carrying straight conductor experiences a force when placed perpendicular to the direction of magnetic field.
Reason (R): The net charge on a current carrying conductor is always zero. (CBSE Board Paper 2023)
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Assertion (A) is false, but Reason (R) is true.
Q5. The change in magnetic field lines in a coil is the cause of induced electric current in it. Name the underlying phenomenon. (CBSE Board Paper 2020)
CBSE Class 10 Metals and Non-metals Board Questions
Q1. No chemical reaction takes place when granules of a solid, A, are mixed with the powder of another solid, B. However when the mixture is heated, a reaction takes place between its components. One of the products, C, is a metal and settles down in the molten state while the other product, D, floats over it. It was observed that the reaction is highly exothermic.
(i) Based on the given information make an assumption about A and B and write a chemical equation for the chemical reaction indicating the conditions of reaction, physical state of reactants and products and thermal status of reaction.
(ii) Mention any two types of reactions under which above chemical reaction can be classified. (CBSE Board Paper 2010)
Q2. The colours of aqueous solutions of CuSO4 and FeSO4 as observed in the laboratory are: (CBSE Board Paper 2012)
(A) pale green and light blue respectively
(B) light blue and dark green respectively
(C) dark blue and dark green respectively
(D) dark blue and pale green respectively
Q3. The colour of an aqueous solution of zinc sulphate as observed in the laboratory is: (CBSE Board Paper 2011)
(1) Green
(2) Yellow
(3) Blue
(4) Colourless
Q4. (a) Write the steps involved in the extraction of pure metals in the middle of the activity series from their carbonate ores.
(b) How is copper extracted from its sulphide ore? Explain the various steps supported by chemical equations. Draw labelled diagram for the electrolytic refining of copper. (CBSE Board Paper 2018)
Q5. 1 g of copper powder was taken in a China dish and heated. What change takes place on heating? When hydrogen gas is passed over this heated substance, a visible change is seen in it. Give the chemical equations of reactions, the name and the color of the products formed in each case. (CBSE Board Paper 2020)
CBSE Class 10 Our Environment Board Questions
Q1. What is the important function of presence of ozone in earth’s atmosphere? (CBSE Board Paper 2011)
Q2. (i) State the essential function performed by ozone at the higher levels of the atmosphere.
(ii) Why was there a sharp drop in the amount of ozone in the atmosphere in 1980's. (CBSE Board Paper 2023)
Q3. Write one difference between biodegradable and non-biodegradable wastes. List two impacts of each type of the accumulated waste on environment if not disposed off properly. (CBSE Board Paper 2023)
Q4. (a) What is an ecosystem? List its two main components.
(b) We do not clean ponds or lakes, but an aquarium needs to be cleaned regularly. Explain. (CBSE Board Paper 2013)
Q5. Give reason to justify the following:
(a) The existence of decomposers is essential in a biosphere.
(b) Flow of energy in a food chain is unidirectional. (CBSE Board Paper 2016)
CBSE Class 10 Periodic Classification of Elements Board Questions
Q1. Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electronic shells but different number of electrons in their outermost shell. It was found that elements A and G combine to form an ionic compound. This compound is added in a small amount to almost all vegetable dishes during cooking. Oxides of elements A and B are basic in nature while those of E and F are acidic. The oxide of D is almost neutral. Based on the above information answer the following questions:
(i) To which group or period of the periodic table do the listed elements belong?
(ii) What would be the nature of compound formed by a combination of elements B and F?
(iii) Which two of these elements could definitely be metals?
(iv) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
(v) If the number of electrons in the outermost shell of elements C and G be 3 and 7 respectively, write the formula of the compound formed by the combination of C and G. (CBSE Board Paper 2010)
Q2. (i) How do you calculate the possible valency of an element from the electronic configuration of its atoms?
(ii) Calculate the valency of element X whose atomic number is 9. (CBSE Board Paper 2011)
Q3. Two elements X and Y belong to group 1 and 2 respectively in the same period of periodic table. Compare them with respect to:
(i) the number of valence electrons in their atoms
(ii) their valencies
(iii) metallic character
(iv) the sizes of their atoms
(v) the formulae of their oxides
(vi) the formulae of their chlorides (CBSE Board Paper 2011)
Q4. Write the number of periods the Modern Periodic Table has. State the changes in valency and metallic character of elements as we move from left to right in a period. Also state the changes, if any, in the valency and atomic size of elements as we move down a group. (CBSE Board Paper 2015)
Q5. (a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation or all the three attempts.
(b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass. State Modern periodic law. (CBSE Board Paper 2018)
CBSE Class 10 Sources of Energy Board Questions
Q1. What are fossil fuels? Write two disadvantages of burning fossil fuels. (CBSE Board Paper 2010)
Q2. What are non-renewable resources of energy? Give two examples of such resources. (CBSE Board Paper 2011)
Q3. Write the energy conversion that takes place in a hydropower plant. (CBSE Board Paper 2018)
Q4. Why is biogas considered an excellent fuel? (CBSE Board Paper 2019)
Q5. Write the name of the main constituent of Biogas. Also, state its percentage. (CBSE Board Paper 2019)
CBSE Class 10 Sustainable Management of Natural Resources Board Questions
Q1. List and explain any two advantages associated with water harvesting at community level. (CBSE Board Paper 2013)
Q2. List three problems which arise due to construction of big dams. Suggest a solution for these problems. (CBSE Board Paper 2012)
Q3. What is water harvesting? List two main advantages associated with water harvesting at the community level. Write two causes for the failure of sustained availability of groundwater. (CBSE Board Paper 2019)
Q4. Why is an equitable distribution of resources essential in a society? List two forces which are against such distribution. (CBSE Board Paper 2017)
Q5. What is meant by wildlife? How is it important for us? (CBSE Board Paper 2017)
CBSE Class 10 The Human Eye and the Colourful World Board Questions
Q1. Name the part of our eyes that helps us to focus near and distant objects in quick succession. (CBSE Board Paper 2010)
Q2. (a) Write the function of each of the following parts of the human eye:
Cornea; iris; crystalline lens; ciliary muscles
(b) Millions of people in the developing countries of the world are suffering from corneal blindness. These persons can be cured by replacing the defective cornea with the cornea of a donated eye. A charitable society of your city has organised a campaign in your neighbourhood in order to create awareness about this fact. If you are asked to participate in this mission, how would you contribute in this noble cause?
(i) State the objective of organising such campaigns.
(ii) List two arguments which you would give to motivate the people to donate their eyes after death.
(iii) List two values which are developed in the persons who actively participate and contribute in such programmes. (CBSE Board Paper 2016)
Q3. What is a rainbow? Draw a labelled diagram to show its formation. (CBSE Board Paper 2023)
Q4. The colour of clear sky from the earth appears blue but from the
space it appears black. Why? (CBSE Board Paper 2023)
Q5. Which of the following statements is not true for scattering of light? (CBSE Board Paper 2017)
(a) Colour of the scattered light depends on the size of particles of the atmosphere.
(b) Red light is least scattered in the atmosphere.
(c) Scattering of light takes place as various colours of white light travel with different speed in air.
(d) The fine particles in the atmospheric air scatter the blue light more strongly than red. So the scattered blue light enters our eyes.
CBSE Class 10 Science Syllabus 2025-26
The Central Board of Secondary Education (CBSE) has released the Science Syllabus for Class 10 for the 2025-26 academic year. This Science Syllabus outlines the course structure, chapters, and topics that students will need to study in the subject. The CBSE Class 10 Science syllabus covers a wide range of topics, including Number Systems, Algebra, Coordinate Geometry, Geometry, Trigonometry, Mensuration and Statistics & Probability. It is divided into units with specific weightage, helping students plan their preparation effectively. The Class 10th Science unite-wise chapters and weightage are provided below :
| Unit Name | Chapter Name |
Weightage in Marks |
|
Chemical Substances-Nature and Behaviour |
Chemical Reactions and Equations |
25 |
| Acids, Bases and Salts | ||
| Metals and Non-metals | ||
| Carbon and its Compounds | ||
|
World of Living |
Life processes |
25 |
| Control and co-ordination in animals and plants | ||
| Reproduction | ||
| Heredity and Evolution | ||
| Natural Phenomena | Natural Phenomena | 12 |
|
Effects of Current |
Effects of Current |
13 |
| Magnetic effects of current | ||
| Natural Resources | Our environment | 5 |
CBSE Class 10 Science Exam Pattern 2025-26
CBSE has released the exam pattern and marking scheme for the 2025-26 academic year. Based on the official question paper design shared along with the syllabus, the board will follow the same exam pattern and marking scheme as in 2024-25. The CBSE Class 12 Science board exam for 2025-26 consists of a theory paper of 80 marks and remaining 20 marks for practical exam. The question paper will be divided into three sections- Section A (Biology), Section B (Chemistry) and Section C (Physics):
| Section | Question Type | Number of Questions | Marks |
| A |
|
16 | 30 |
| B |
|
13 | 25 |
| C |
|
10 | 25 |
| Total | 39 | 80 | |
Check the latest and detailed CBES Class 10th Science Exam Pattern 2025-26 with Marking Scheme.