CBSE Class 10 Science Case Study Questions Chapter Wise

CBSE Class 10 Science Case Study Questions:  The CBSE Class 10 Science Board Exam 2025 is approaching, and students are putting in their best efforts to score high marks. To support their preparation, important Case Study Questions from Class 10 Science are essential for practice. These questions test scientific concepts, critical thinking, and problem-solving skills by applying knowledge to real-life scenarios. Since Case-Based Questions carry 12 marks, accounting for 15% of the total exam marks, it is crucial for students to master them. 

Regular practice of Class 10 Science Case Study Questions enhances conceptual understanding and exam readiness. To help students, we have provided a downloadable PDF with solutions for effective learning and better performance in the exams.

Class 10 Science Blueprint 2025 | Class 10 Science Important Topics | Class 10 Science Most Repeated Questions 2025

What are Case Study Based Questions?

Case Study-Based Questions are a type of exam question that require students to apply conceptual knowledge to real-life scenarios. These questions are designed to assess critical thinking, problem-solving, and analytical skills rather than just memorization.

In CBSE Class 10 Science Board Exam 2025, Case Study Questions play a significant role, carrying 12 marks, which is about 15% of the total exam weightage. These questions present a short passage, experiment, or situation related to a scientific concept, followed by multiple-choice, short-answer, or descriptive questions.

CBSE Class 10 Science Case Study Questions Chapter Wise

Case Study 1:

The earlier concept of oxidation and reduction was defined based on the addition or removal of oxygen or hydrogen. Oxidation refers to the addition of oxygen to a substance or the removal of hydrogen from a substance. Conversely, reduction refers to the addition of hydrogen to a substance or the removal of oxygen from a substance. The substance that donates oxygen or removes hydrogen in an oxidation reaction is called the oxidizing agent, while the substance that donates hydrogen or removes oxygen in a reduction reaction is called the reducing agent. These concepts are essential in understanding redox reactions, which are widely used in industries, biological processes, and chemical reactions.

Questions 1: In the reaction: CuO + H₂ → Cu + H₂O, identify the oxidizing and reducing agents.
Answer: Oxidizing agent: CuO (Copper(II) oxide) because it donates oxygen.
Reducing agent: H₂ (Hydrogen gas) because it removes oxygen from CuO and itself gets oxidized to H₂O.

Which of the following statements is true about oxidation?
a) It involves the removal of oxygen from a substance.
b) It involves the addition of hydrogen to a substance.
c) It involves the addition of oxygen to a substance.
d) It is the same as reduction.

Answer: (c) It involves the addition of oxygen to a substance.

Question 2: Define an oxidizing agent and give an example.
Answer: An oxidizing agent is a substance that gives oxygen to another substance or removes hydrogen from it during a reaction. Example: Potassium permanganate (KMnO₄) is a strong oxidizing agent.

In the reaction: Zn + HCl → ZnCl₂ + H₂, which element undergoes oxidation and which undergoes reduction?
Answer:

Zinc (Zn) undergoes oxidation as it loses electrons to form Zn²⁺.
Hydrogen ions (H⁺) from HCl undergo reduction as they gain electrons to form H₂ gas.

Question 3: Why is oxidation always accompanied by reduction?
Answer: Oxidation and reduction always occur together in a redox reaction because when one substance loses electrons (oxidation), another substance must gain them (reduction) to maintain the balance of charge.

Case Study 2

A student performed an experiment by adding small iron nails to a solution of copper sulfate (CuSO₄) in a beaker. After a few minutes, he observed that the blue color of the solution started fading, and a reddish-brown deposit appeared on the iron nails.

Questions 1: What type of chemical reaction is observed in the experiment?
Answer: This is a displacement reaction where iron (Fe) replaces copper (Cu) from copper sulfate.

Question 2: Write the balanced chemical equation for the reaction.
Answer: Fe + CuSO₄ → FeSO₄ + Cu

Question 4: Why does the blue color of the solution fade?
Answer: The blue color fades because copper sulfate is converted into iron sulfate, which is greenish in color.

Question 5: What is the brownish-red substance deposited on the iron nails?
Answer: The brownish-red deposit is copper metal (Cu), which is displaced from the solution.

Question 6: Which metal is more reactive in this reaction? Justify your answer.
Answer: Iron (Fe) is more reactive than copper (Cu), which is why it replaces copper from its sulfate solution.

Chapter 2: Acids, Bases, and Salts

Case Study 3:

A student was given three colorless solutions labeled A, B, and C. He tested them with blue litmus paper and found that solution A turned the litmus red, solution B had no effect on the litmus, and solution C turned the red litmus blue.

Questions 1: Classify the three solutions as acidic, basic, or neutral.
Answer: Solution A: Acidic (Turns blue litmus red)
Solution B: Neutral (No change in litmus)
Solution C: Basic (Turns red litmus blue)

Question 2: Which ion is responsible for the acidic nature of solution A?
Answer: H⁺ (Hydrogen ion) is responsible for the acidic nature.

Question 3: If solution C is sodium hydroxide (NaOH), write its reaction with hydrochloric acid (HCl).
Answer: NaOH + HCl → NaCl + H₂O (Neutralization reaction)

Question 4: Which solution could be distilled water?
Answer: Solution B (neutral) could be distilled water as it does not affect litmus paper.

Question 5: Which indicator, apart from litmus, can be used to confirm the nature of these solutions?
Answer: Phenolphthalein can be used. It remains colorless in acids and neutral solutions but turns pink in bases.

Chapter 3: Metals and Non-Metals

Case Study 3:

A student observed that when a small piece of sodium metal was dropped into water, it reacted vigorously, producing a hissing sound and forming a colorless solution. A gas was also evolved, which burned with a pop sound.

Questions 1: What type of reaction is taking place between sodium and water?
Answer: This is a highly exothermic reaction where sodium reacts with water to form sodium hydroxide and hydrogen gas.

Question 2: Write the balanced chemical equation for the reaction.
Answer: 2Na + 2H₂O → 2NaOH + H₂

Question 3: What is the colorless solution formed?
Answer: The solution is sodium hydroxide (NaOH), which is basic in nature.

Question 4: Why does the evolved gas burn with a ‘pop’ sound?
Answer: The gas is hydrogen (H₂), which is highly flammable and burns with a characteristic pop sound.

Question 5: What precaution should be taken while handling sodium metal?
Answer: Sodium should be stored in kerosene to prevent its reaction with moisture or air.

Chapter 4: Carbon and Its Compounds

Case Study 4:

A chemistry teacher demonstrated an experiment by heating ethanol in the presence of alkaline potassium permanganate (KMnO₄) solution. The purple color of the KMnO₄ solution slowly faded, and the solution became colorless.

Questions 1: What type of reaction is taking place?
Answer: This is an oxidation reaction, where ethanol is oxidized to ethanoic acid.

Question 2: Write the chemical equation for the reaction.
Answer: CH₃CH₂OH + [O] → CH₃COOH + H₂O

Question 3: Why does the purple color of potassium permanganate disappear?
Answer: KMnO₄ acts as an oxidizing agent and gets reduced, losing its color.

Question 4: Name the product formed after the oxidation of ethanol.
Answer: The product is ethanoic acid (CH₃COOH).

Question 5: What is the use of ethanoic acid in daily life?
Answer: Ethanoic acid is used in vinegar, which is commonly used in cooking and food preservation.

Chapter 5: Life Processes

Case Study 5:

During a biology experiment, a student placed a potted plant in a dark room for 24 hours. Then, he covered a leaf with black paper and placed the plant in sunlight for a few hours. Later, he tested the leaf with iodine solution and found that only the uncovered parts turned blue-black.

Questions 1: What process is being studied in this experiment?
Answer: The process being studied is photosynthesis.

Question 2: Why was the plant kept in the dark for 24 hours before the experiment?
Answer: This was done to deplete the stored starch so that fresh starch production could be observed.

Question 3: Why did the uncovered part of the leaf turn blue-black?
Answer: The uncovered part performed photosynthesis and produced starch, which reacts with iodine to turn blue-black.

Question 4: What conclusion can be drawn from this experiment?
Answer: Light is essential for photosynthesis as the covered part did not turn blue-black.

Question 5: Write the chemical equation for photosynthesis.
Answer: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (in the presence of sunlight and chlorophyll).

Case Study Questions Class 10 Science High Level Questions

Case Study 1:

A scientist conducts an experiment with pea plants to study the inheritance of flower color. He crosses a pure-breeding purple-flowered plant (PP) with a pure-breeding white-flowered plant (pp). In the F₁ generation, all plants have purple flowers. However, when these F₁ plants (Pp) are self-crossed, the F₂ generation shows a 3:1 ratio of purple to white flowers.

1. Explain why all F₁ plants have purple flowers despite having one allele for white flowers.
   Answer: The purple flower trait is dominant (P), so even one dominant allele (P) in the heterozygous condition (Pp) masks the white flower trait.
2. What is the expected genotype ratio in the F₂ generation?
   Answer: The genotype ratio is 1 PP : 2 Pp : 1 pp (1 homozygous dominant, 2 heterozygous, and 1 homozygous recessive).
3. If a white-flowered plant (pp) from the F₂ generation is crossed with an F₁ plant (Pp), what will be the expected phenotype ratio?
   Answer: The expected ratio is 1 purple : 1 white, as the cross is Pp × pp, giving 50% Pp (purple) and 50% pp (white).
4. Which Mendelian principle explains this experiment?
   Answer: The experiment follows Mendel’s Law of Segregation, which states that allele pairs separate during gamete formation, and each gamete receives only one allele.
5. What would be the result if the inheritance followed incomplete dominance instead of complete dominance?
   Answer: If incomplete dominance occurred, the F₁ generation would have light purple flowers (a blend of purple and white), instead of all being purple.

Chapter: Electricity

Case Study 2:

A household electrical circuit consists of a fuse, a fan, a light bulb, and a refrigerator connected in parallel to a 230V power supply. One day, the refrigerator malfunctions and causes a short circuit, leading to a sudden spike in current. However, the main fuse blows, preventing any further damage to other appliances.

1. Why is a fuse used in household wiring?
   Answer: A fuse prevents excessive current flow by melting when the current exceeds a safe limit, thereby breaking the circuit and protecting appliances.
2. Why are household appliances connected in parallel instead of in series?
   Answer: Parallel connections ensure that each appliance receives the full 230V supply and can operate independently. In a series circuit, if one device fails, the entire circuit would stop working.
3. What happens if a fuse of higher rating (e.g., 20A) is used instead of the recommended 5A?
   Answer: A higher-rated fuse will not blow in time during a fault, leading to potential overheating, damage, or fire hazards.
4. What type of wire is used in fuse elements, and why?
   Answer: Fuse wires are made of low-melting-point metals like tin or lead, allowing them to melt quickly when excessive current flows.
5. How does a circuit breaker (MCB) differ from a traditional fuse?
   Answer: An MCB automatically switches off the circuit during overloads and short circuits, whereas a fuse must be replaced after it blows.

Chapter: Magnetic Effects of Electric Current

Case Study 3:

A railway signaling system uses electromagnets to control track switching. When an electric current flows through the coil of an electromagnetic relay, it attracts an iron lever, which changes the direction of the train. However, during a power failure, the electromagnet does not work, and the train remains on its original track.

1. Why does the electromagnet stop working during a power failure?
   Answer: An electromagnet requires an electric current to generate a magnetic field. Without electricity, the magnetic effect disappears, and the switch mechanism fails.
2. How is the working principle of an electromagnet applied in electric bells?
   Answer: In an electric bell, an electromagnet attracts an iron armature, which strikes the bell. When the circuit breaks, the armature returns to its original position, repeating the process.
3. What will happen if the strength of the electromagnet is increased?
   Answer: Increasing the electromagnet’s strength will increase its magnetic force, allowing it to control heavier track switches or operate more efficiently.
4. Why are soft iron cores used in electromagnets instead of steel?
   Answer: Soft iron can be magnetized and demagnetized quickly, whereas steel retains magnetism, making it unsuitable for applications like relays.
5. Which rule is used to determine the direction of the magnetic field around a current-carrying conductor?
   Answer: Right-Hand Thumb Rule, which states that if the thumb points in the direction of current flow, the curled fingers show the direction of the magnetic field.

Chapter: Human Eye and the Colourful World

Case Study 4:

A student in a dark room looks through a prism at white light passing through a small slit. He observes a band of seven colors on a screen. Later, when he views a rainbow in the sky, he realizes that a similar process is occurring naturally.

1. What is the phenomenon responsible for the formation of the spectrum in this experiment?
   Answer: Dispersion of light, where white light splits into its constituent colors when passing through a prism.
2. Why does a rainbow form in the sky after rainfall?
   Answer: A rainbow forms due to dispersion, refraction, and total internal reflection of sunlight in raindrops.
3. Which color deviates the most and which deviates the least in a prism?
   Answer: Violet deviates the most, and red deviates the least because violet has a shorter wavelength and experiences more refraction.
4. What is the sequence of colors observed in a rainbow?
   Answer: VIBGYOR (Violet, Indigo, Blue, Green, Yellow, Orange, Red).
5. Why does light bend when passing through a prism but not in a glass slab?
   Answer: In a prism, light rays enter at an angle, causing unequal refraction. In a glass slab, refraction occurs at both surfaces equally, so the emergent ray remains parallel to the incident ray.

Chapter: Sources of Energy

Case Study 5:

A village installs a biogas plant to meet its energy needs. The plant uses cow dung, crop waste, and sewage to produce methane gas, which is used for cooking and lighting. The villagers notice that the leftover slurry from the plant improves soil fertility.

1. Which process takes place in a biogas plant to produce methane?
   Answer: Anaerobic decomposition of organic matter by bacteria produces methane.
2. Why is biogas considered a clean fuel?
   Answer: Biogas burns without producing smoke and has a high calorific value, making it environmentally friendly.
3. How does the biogas plant contribute to sustainable development?
   Answer: It reduces waste, provides renewable energy, and improves soil fertility by using the leftover slurry as organic fertilizer.
4. What are the main components of biogas?
   Answer: Methane (CH₄), carbon dioxide (CO₂), hydrogen (H₂), and traces of hydrogen sulfide (H₂S).
5. Why is biogas better than firewood as a fuel?
   Answer: Biogas produces more energy, does not cause deforestation, and does not release harmful pollutants like firewood.