CBSE 2024-25 Competency-Based Questions With Answers: As students prepare for the CBSE Class 10 Science exams in 2025, understanding chemical reactions and equations is essential. This topic explains how substances change and react with one another, forming new materials. In this article, we will focus on competency-based questions (CBQs) that help students think critically and apply their knowledge to real-life situations. These questions will not only test what you know but also how well you can use that information.
The Central Board of Secondary Education has already released the question PDFs to help students prepare well. Students need to check these CBQs and solve them to know the question typology that they might face in the final exam.
CBSE Class 10 Science Chemical Reactions and Equations Competency-Based Questions
The more you solve, the more you will improve. Thus, it is suggested that students should try to target as many practice papers as possible. The competency-based questions provided here are CBSE-designed and are a must to be solved before the exam.
| Q. No | Question | Marks |
| Free Response Question/ Subjective Question | ||
| Q.1 | Photographic film consists of a gelatin emulsion with silver halide grains layered onto a film base. The halides that are used are silver chloride, bromide or iodide. The photographic film is usually stored in metal containers to protect it from light. Write the chemical equation for the possible chemical reaction that this method of storing photographic film is preventing. | 1 |
| Q.2 | Trupti mixed one teaspoon of baking soda in 500 g of cake mixture. She kept the mixture aside for 5 minutes. Geeta mixed one teaspoon of baking powder in 500 g of the same cake mixture. She also kept the mixture aside for 5 minutes. She then baked the two cakes together in the same oven. Whose cake is likely to rise higher? Justify your answer. | 3 |
| Q.3 | While cooking in an aluminum vessel, Sudeshna burned some food till all that was left was a completely charred and black residue. She just left the blackened vessel heating on the stove. After an hour she found that the vessel was completely clean, with no trace of any blackness.
| 2 |
Answer Key & Marking Scheme
| Q. No | Answers | Marks |
| Q.1 | 1 | |
| Q.2 | Trupti's cake will rise more. [1 mark] Baking powder is a mixture of sodium bicarbonate and tartaric acid. [1 mark] - Baking soda is pure sodium bicarbonate. Hence one teaspoon of baking soda contains more bicarbonate than baking powder and releases more carbon dioxide than baking powder.. [1 marks] | 3 |
| Q.3 |
C + O2 ---> CO2
| 2 |
Download these questions in PDF from the link below:
CBSE Class 10 Science Chemical Reactions and Equations Weightage in 2025 Board Exams
For the CBSE Class 10 Science exams in 2024-25, the unit-wise weightage is as follows. The first unit, "Chemical Substances - Nature and Behaviour," is worth 25 marks. The second unit, "World of Living," also carries 25 marks. The third unit, "Natural Phenomena," is worth 12 marks. The fourth unit, "Effects of Current," has a weightage of 13 marks. Finally, the fifth unit, "Natural Resources," is worth 5 marks. In total, the exam will have 80 marks. Understanding the weightage of each unit can help students focus their studies effectively.
Thus, considering the marks allocated to unit-I, the Chemical Reactions and Equations Weightage in 2025 Board Exams will be between 10 to 15.
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