CBSE Class 10 Science Most Important Questions 2025-26: Chapterwise Repeated Qs PDF

Most Important Questions of CBSE Class 10 Science: Chapter Wise

CBSE class 10 have a total of 13 chapters mix of physics, chemistry and biology. In this section below, you will find the chapterwise repeated questions which appeared in the board exam the previous year, and these questions are expected to be in the final exam of this year as well. To download the complete important questions for class 10 science with answers PDF, click on the link below.

Download PDF | Most Important Questions of CBSE Class 10 Science

Important Questions for Class 10 Science Chemical Reactions and Equations

Below are some of the important questions for CBSE Class 10 Science Chapter 1. Check more questions by downloading the link given above.

Question 1: Solid calcium oxide was taken in a container, and water was added slowly to it.

(a) Write the observations.

(b) Write the chemical formula of the product formed.

Question 2: What change in colour is observed when white silver chloride is left exposed to sunlight? State the type of chemical reaction in this change.

Question 3: In the electrolysis of water,

A. Name of the gases liberated at the anode & cathode.

B. Why is it that the volume of gas collected on one electrode is two times that on the other electrode?

C. What would happen if dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ is not added to water?

Question 4: A shining metal ' M ' on burning gives a dazzling white flame and changes to a white powder ' N '.

A. Identify ' M ' and ' N '.

B. Represent the above reaction in the form of a balanced chemical equation.

C. Does ' $M$ ' undergo oxidation or reduction in this reaction? Justify.

Important Questions for Class 10 Science Acids, Bases and Salts

CBSE 10th Science Important Questions 2025-26 for Chapter 2 are given below. Check the answer to these questions by downloading the PDF, which is given above in this article.

Question 1: List the important products of the chlor-alkali process. Write one important use of each.

Question 2:

(a) Identify the acid and the base whose combination forms the common salt that you use in your food. Write the chemical formula and chemical name of the salt.

(b) What is rock salt?

(c) Mention its colour and the reason due to which it has this colour.

Question 3: Write the chemical equations when zinc granules react with:

(a) Sulphuric acid

(b) Hydrochloric acid

Question 4: How is sodium hydroxide produced? Write the balanced chemical equation also. Why is this process called the chlor-alkali process? In this process name the products given off at:

(a) anode

(b) cathode.

Important Questions for Class 10 Science Metals and Non-metals

Most Important Questions for Class 10 Science Term 21 Chapter 3 metal and mon metals are given below:

Question 1: Why do ionic compounds conduct electricity in the molten state and not in solid state?

Question 2: The reaction of metal $X$ with ${\mathrm{Fe}}_2{\mathrm{O}}_3$ is highly exothermic and is used to join railway tracks. Identify metal $X$. Write the chemical equation for the reaction.

Question 3: Zinc is a metal found in the middle of the activity series of metals. In nature, it is found as a carbonate ore, ${\mathrm{ZnCO}}_3$. Mention the steps carried out for extraction from the ore.

Question 4: Differentiate between roasting and calcination giving chemical equations for each.

Question 5: Why are copper vessels corroded with a green coating in the rainy season?

Important Questions for Class 10 Science Carbon and its Compounds

Some of the Expected Questions for Class 10 Science 2025-26 of chapter 4 are given below:

Question 1: Draw the electron dot structure of Nitrogen.

Question 2: Write the chemical formula of benzene and draw its structure.

Question 3: What will you observe on adding a $5\mathrm{\%}$ alkaline ${\mathrm{KMnO}}_4$ solution drop by drop to some warm ethanol taken in a test tube? Write the name of the compound formed during the above chemical reaction.

Question 4: Why do covalent compounds have low melting and boiling points?

Important Questions for Class 10 Science Life Processes

Class 10 Science Board Exam 2025-26 Expected Questions of the chapter Life Process are given below:

Question 1:

(a) What is double circulation?

(b) Why is the separation of the right side and the left side of the heart useful? How does it help birds and mammals?

Question 2: Explain the ways in which glucose is broken down in the absence or storage of oxygen?

Question 3:

(a) Write two water-conducting tissues present in plants. How does water enter continuously into the root xylem?

(b) Explain why plants have low energy needs as compared to animals.

Question 4: In single-celled organisms, diffusion is sufficient to meet all their requirements for food, gas exchange, or removal of waste, but it is not in the case of multicellular organisms. Explain the reason for the difference.

Important Questions for Class 10 Science Control and Coordination

Check CBSE 10th Science Important Questions 2025-26 of chapter control and coordination

Question 1: Name a plant hormone responsible for bending of a shoot of a plant when it is exposed to unidirectional light. How does it promote phototropism?

Question 2: With the help of suitable examples explain the terms phototropism, geotropism and chemotropism,

Question 3: Draw a diagram of the cross-sectional view of the human brain label the parts of the brain with the functions.

Question 4: How does the feedback mechanism regulate hormone secretion? Explain with the help of an example?

Important Questions for Class 10 Science How do Organisms Reproduce?

Most Important Questions for Class 10 Science Term1 chapter how How do Organisms Reproduce is given below:

Question 1: Difference between the asexual and sexual reproduction? Also, give one example of each.

Question 2: Describe reproduction by spores in Rhizopus.

Question 3: List three techniques that have been developed to prevent pregnancy. Which one of these techniques is not meant for males?

Question 4: How does the use of these techniques have a direct impact on the health and prosperity of a family?

Important Questions for Class 10 Science Heredity

Expected Questions for Class 10 Science 2025-26 chapter Heredity is given below:

Question 1: Mention any two points of difference between acquired and inherited traits. If the tail of a mouse is cut for twenty one generations, will the tail occur in the twenty second generation of that mouse? Give reason to support your answer.

Question 2: Two pea plants- one with round yellow seeds (RRYY) and another with wrinkled green (rryy) seeds produce F1 progeny that have round, yellow (RrYy) seeds. When F1 plants are self-pollinated, which new combination of characters is expected in F2 progeny? How many seeds with these new combinations of characters will be produced when a total 160 seeds are produced in F2 generation? Explain with reason.

Important Questions for Class 10 Science Light – Reflection and Refraction

CBSE 10th Science Important Questions 2025-26 of chapter light are given below:

Question 1: State the two laws of reflection of light.

Question 2: The absolute refractive indices of glass and water are 1.5 and 1.33 respectively. In which medium does light travel faster? Calculate the ratio of speeds of light in the two media.

Question 3: The image of a candle flame placed at a distance of 30 cm from a mirror is formed on a screen placed in front of the mirror at a distance of 60 cm from its pole. What is the nature of the mirror? Find its focal length. If the height of the flame is 2.4 cm, find the height of its image. State whether the image formed is erect or inverted.

Important Questions for Class 10 Science The Human Eye and the Colourful World

Question 1: What is 'dispersion of white light'? State its cause. Draw a ray diagram to show the dispersion of white light by a glass prism.

Question 2: How will you use two identical glass prisms so that a narrow beam of white light incident on one prism emerges out of the second prism as white light? Draw and label the ray diagram.

Question 3: Draw a ray diagram to show the refraction of light through a glass prism. Mark on it (a) the incident ray, (b) the emergent ray and (c) the angle of deviation.

Important Questions for Class 10 Science Electricity

Question 1:

(a) Prove that the equivalent resistance of three resistors R1, R2 and R3 in series is R1 + R2 + R3.

(b) You have four resistors of 8 each. Show how would you connect these resistors to have effective resistance of $8\mathrm{\Omega }$ ?

Question 2: State Ohm's law. Draw a labelled circuit diagram to verify this law in the laboratory. If you draw a graph between the potential difference and current flowing through a metallic conductor, what kind of curve will you get? Explain how would you use this graph to determine the resistance of the conductor.

Important Questions for Class 10 Science Electricity

Question 1: State whether an alpha particle will experience any force in a magnetic field if (alpha particles are positively charged particles) (i) it is placed in the field at rest.

(ii) it moves in the magnetic field parallel to field lines.

(iii) it moves in the magnetic field perpendicular to field lines. Justify your your answer in each case.

Question 2: Mention and explain the function of an earth wire. Why it is necessary to earth metallic appliances?

(CBSE 2014, 2016, 2020)

Important Questions for Class 10 Science Magnetic Effects of Electric Current

Question 1: State whether an alpha particle will experience any force in a magnetic field if (alpha particles are positively charged particles) (i) it is placed in the field at rest.

it moves in the magnetic field parallel to field lines.

it moves in the magnetic field perpendicular to field lines. Justify your your answer in each case.

Question 2: Mention and explain the function of an earth wire. Why it is necessary to earth metallic appliances?

Name and state the rule which is used to determine the direction of force on a current carrying conductor placed in a magnetic field.

Important Questions for Class 10 Science Our Environment

Question 1: How is ozone formed in the higher levels of the atmosphere?" Damage to the ozone layer is a cause of concern". Justify this statement.

Question 2: We do not clean ponds or lakes, but an aquarium needs to be cleaned regularly. Explain.

Question 3: Why are green plants called the producers?

10 Most Important for Questions from Class 10 Science Chapters

Question 1: Write the chemical equation of the reaction in which the following changes take place with an example of each.

(a) Change in color (b) Change in temperature

Question 2: Give the reasons for the following:

(i) Only one half of the water molecule is shown in the formula of plaster of Paris.

Question 3: Why are copper vessels corroded with a green coating in the rainy season?
Question 4: What is meant by a homologous series of carbon compounds? Write the general formula of

1. Alkenes (b) alkynes

Question 5: Draw a diagram of the human alimentary canal and label the following:

part in which starch digestion is initiated

1. An organ in which bile is stored

2. The gland that secretes digestive enzymes as well as hormones.

3. Part of the alimentary canal where water is reabsorbed.

4. Parts of the gut where finger-like projections are present to facilitate absorption of digested food.

Question 6: Name the part of human brain which control the voluntary and involuntary actions.

Question 7: Define pollination. Explain the different types of pollination. List two agents of pollination. How does suitable pollination lead to fertilisation?

Question 8: In an asexually reproducing species, if a trait X exists in 5% of a population and trait Y exists in 70% of the same population, which of the two traits is likely to have arisen earlier? Give a reason.

Question 9: A student is unable to see clearly the words written on the blackboard placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the met2hod4 of correcting it.

Question 10: Draw a schematic diagram of a circuit consisting of a battery of 3 cells of 2 V each, a combination of three resistors of 10Ω, 20Ω and 30Ω connected in parallel, a plug key and an ammeter, all connected in series. Use this circuit to find the value of the following:

1. Current through each resistor

2. Total current in the circuit

3. otal effective resistance of the circuit.

How CBSE 10th Most Important Questions of Science Will Help?

Solving the most important question of CBSE class 10 science can be a master change for students who are preparing for the board exam 2025-26. Some of the important pointers are listed below:

• CBSE 10th science Important questions will help students to know the types of questions being asked from that particular chapter in recent years and which may come in this CBSE class 10 exam 2025-26 as well.

• By solving most repeated questions of CBSE Class 10 students will be able to analyse their performance, meaning whether they are able to solve the question easily, if not, then students should work on that question.

• As you can see, questions from each chapter are repeated from the previous year, which allows students to analyse the pattern of questions, which will help students to utilise the time in the right direction for CBSE 10th preparation.

• By going through the important questions of CBSE class 10th science, students will not be required to read the syllabus; they can read the syllabus according to the pattern of questions, like in electricity, Ohm's law derivation is being asked, then they must focus on that particular question. This is valid for all other chapters as well.

Additional Study Materials for Class 10 Science Preparation