CBSE Board Exams 2026: Assessments play a crucial role in helping students build confidence and stay aligned with their exam preparation. Sample papers and competency-based practice questions enable learners to evaluate their understanding of the syllabus and track their conceptual clarity ahead of the final examinations.
The Central Board of Secondary Education (CBSE) has increased the difficulty level of the 2026 board exams with significant changes in the question paper pattern. The revised structure places greater emphasis on conceptual understanding and real-life application of knowledge.
Students will face more competency-based questions, including case studies, data interpretation, source-based items, and situational problem-solving tasks. Under the new pattern, 50 per cent of the questions will test the application of concepts, while the remaining portion will assess reasoning, clarity of thought, and analytical ability.
CBSE has now released competency-focused practice questions for the Class 10 Science paper. Students appearing for the 2026 exams can access these topic-wise questions to familiarise themselves with the expected level and format of questions.
Take a look at the following competency-based practice questions.
Chapter: Chemical Reactions and Equations
Q1. Which of the following is an example of a simple displacement reaction?
The electrolysis of water
The burning of methane
The reaction of a metal with an acid
Q2. Which of the following is a necessary condition for all chemical reactions?
The reactants should be in the same state.
Energy should be supplied to the reactants.
The reactants should be at the same temperature.
There should be physical contact between the reactants.
Q3. Given below is the balanced chemical equation for the thermal decomposition of lead nitrate:
2 Pb(NO₃)₂ → 2 PbO + 4 NO₂ + O₂
What do the coefficients of PbO and NOâ‚‚ (2 and 4, respectively) indicate?
The ratio of the number of moles of the two substances produced
The ratio of the number of atoms in the two substances
The ratio of their masses
The ratio of their densities
Q 4. The following chemical equation does not represent a reaction that can occur: 3 Fe (s) + 4 H₂O (l) → FeO (s)
State what needs to be corrected in the equation for it to represent the proper reaction between Fe and Hâ‚‚O.
Q5. Acids can 'dissolve' metals. When metals are added to an acid, they disintegrate and disappear.
(a) State one other observation made when metals react with acids and explain its cause.
(b) If the acid containing the 'dissolved' metal is evaporated, can the metal be recovered? Explain.
(c) Why is the word 'dissolve' placed in quotes? What is the main difference between a metal 'dissolving' in acid and sugar dissolving in water?
Q6. Sunita conducted the following reactions:
(i) Complete neutralisation of 1 mole sodium carbonate with HCl
(ii) Complete neutralisation of 1 mole sodium bicarbonate with HCl
She observed that both reactions produced the same amount of carbon dioxide.
(a) Is her observation correct? Justify.
(b) Compare the amount of salt formed in (i) and (ii).
Chapter 2: Acids, Bases and Salts
Q: 1 Adding which of the following to a colourless solution would give an indication that the solution could possibly be hydrochloric acid?
1 copper metal strips
2 silver metal strips
3 calcium carbonate
4 sodium chloride
Magnetic Effects of Electric Current
Q1. Assertion (A): In an AC generator, current is induced in the coil as it rotates between the poles of a permanent magnet.
Reason (R): The force due to the magnetic field makes the coil rotate in an AC generator.
Choose the correct option:
- Both A and R are true, and R correctly explains A.
- Both A and R are true, but R does not explain A.
- A is true, but R is false.
- A is false, but R is true.
Sources Of Energy
Q1. Water stored in reservoirs behind dams is used to generate hydroelectricity. Which of the following helps generate hydroelectric power?
P) Gravity
Q) Solar energy
- Only P
- Only Q
- Both P and Q
- Neither P nor Q
Q2. Assertion (A): Sunlight received by a solar panel on Earth is lower than that received by a solar panel on a spacecraft.
Reason (R): Sunlight in space is not obstructed by a medium like air.
- Both A and R are true, and R explains A.
- Both A and R are true, but R does not explain A.
- A is true, but R is false.
- A is false, but R is true.
Chapter: Our Environment
Hydrogen is considered a clean fuel with high calorific value. It produces only water upon combustion. Hydrogen is classified based on its production method:
- Green hydrogen: No carbon dioxide is produced.
- Blue hydrogen: Carbon dioxide is produced but captured and stored.
- Grey hydrogen: Carbon dioxide is produced and released into the atmosphere.
Q1. Hydrogen is classified as 'brown' if its production releases both carbon dioxide and carbon monoxide. How is brown hydrogen worse than grey hydrogen?
- It releases a gas that directly causes greenhouse effect.
- It releases carbon stored for millions of years.
- It releases a toxic gas harmful to humans.
- It releases gases that cause acid rain.
Q2. What is the ratio of average energy absorbed by producers to that absorbed by primary consumers?
1:2
2:1
1:10
10:1
Q3. Which of the following correctly describes the flow of energy and nutrients in an ecosystem?
- Bidirectional and cyclic
- Unidirectional and cyclic
- Cyclic and bidirectional
- Cyclic and unidirectional
- Polar Stratospheric Clouds and Ozone Depletion
Q 4: The stratosphere is very dry and rarely allows clouds to form. In the extreme cold of the polar winter, however, stratospheric clouds of different types may form. These clouds are called Polar Stratospheric Clouds (PSCs). Scientists recently discovered that polar stratospheric clouds, long known to play an important role in Antarctic ozone destruction, are occurring with increasing frequency
in the Arctic. These high-altitude clouds form only at very low temperatures help destroy ozone in two ways: (1) They provide a surface which converts benign forms of chlorine into reactive, ozone-destroying forms, and (2) they remove nitrogen
compounds that moderate the destructive impact of chlorine. In recent years, the atmosphere above the Arctic has been colder than usual, and polar stratospheric clouds have lasted into the spring. As a result, ozone levels have been decreasing.
(Information credit: NASA)
(a) How is ozone formed in the outer atmosphere?
(b) Ozone is being continuously destroyed due to extreme low temperatures. However,
ozone formation is also a continuous process. Why is there a depletion in the ozone
layer still?
(c) What can be a positive effect of global warming on the depletion of the ozone
layer?
(d) How does ozone layer depletion impact human health?
Check the list of competency-based practice questions for Class 10 Science here