CBSE 10th Science Set 1 Answer Key 2025 Unofficial (Available)

CBSE 10th Science Set 1 Answer Key 2025 Unofficial is available here (Image Credits: pexels.com).

CBSE 10th Science Set 1 Answer Key 2025: The Central Board of Secondary Education (CBSE) will conduct the 10th Science exam on February 20, 2025. Candidates can go through the CBSE 10th Science set 1 Answer Key 2025 Unofficial here for their reference. The Science Set 1 Answer Key for CBSE 10th has been prepared by subject experts and professionals. Until the release of the final CBSE 10th result, candidates can depend on this unofficial key to evaluate their performance and estimate their scores. The CBSE 10th science examination consisted of 39 questions, all of which were divided into sections: A, B, C, D, and E. Moreover, the students had to attempt Multiple Choice Questions (MCQs), short answer questions, and long answer questions. The CBSE 10th Science Set 1 Answer Key 2025 Unofficially is available below.

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CBSE 10th Science Set 1 Answer Key 2025 Unofficial (Available)

Candidates can check the Unofficial CBSE 10th Science Set 1 Answer Key 2025 in the table below.

Question No.	CBSE 10th Science Set 1 Answer Key 2025 Unofficial (Available)
Q1. The main observations while experimenting with burning magnesium ribbon in the air are: Magnesium ribbon burns with a dazzling white flame. A white powder is formed. Magnesium ribbon vapourises. Aqueous solution of the white powder turns blue litmus to red.	(C) (i) and (ii)
Q2. A metal, M, displaces iron from an aqueous solution of ferrous sulfate but fails to do so in the case of an aqueous solution of aluminum sulfate. The metal Mis	(D) Zinc
Q3. A common feature observed in the crystals of washing soda, copper sulfate, gypsum, and ferrous sulfate is that all	(C) have a fixed number of molecules of water of crystallization in one formula unit of these salts
Q4. A metal, 'X', on treatment with sodium hydroxide liberates a gas 'G'. It also liberates the same gas, 'G' on treatment with dilute sulphuric acid. Based on the above information, 'X' and 'G' respectively are	(C) Zinc and Hydrogen
Q5. The values of a, b, c, and d in the following balanced chemical equation are respectively: 2 R a Pb(NO3)2 heat, b PbO + c NO2 + O2	(D) 2, 2, 4, 1
Q6. During electrolytic refining of copper, the anode, the cathode and the electrolyte used respectively are	(A) Impure copper, pure copper, acidified copper sulfate solution
Q7. If we make a carbon skeleton with four carbon atoms, the two different possible skeletons will be	(B) C-C-C-C; C- C/CC
Q8. Listed below are the steps of nutrition in Amoeba. Select the correct sequence of these steps: Diffusion of simple nutrients into cytoplasm Food vacuole formation Formation of finger-like temporary extensions of cell surface Complex substances are broken into simpler ones Undigested material thrown out of the cell surface	(D) (iii), (iv), (i), (ii), (v)
Q9. Which among the following is not a neural action controlled by the part of the human brain labeled 'X' in the figure above?	(D) Blood Pressure
Q10. The modes of reproduction in Spirogyra and Planaria respectively are	(C) Fragmentation and regeneration
Q11. The plant hormones promoting rapid cell division in seeds and wilting of leaves respectively are	(B) Cytokinins and Abscisic acid
Q12. In aerobic respiration, the steps are breakdown of glucose to pyruvate and its further conversion to carbon dioxide. Both processes respectively occur in -	(D) Cytoplasm and Mitochondria
Q13. To obtain large images of the teeth of patients, the dentist holds the concave mirror in such a manner that the teeth are positioned	(B) between the pole and the focus of the mirror.
Q14. A possible way to restore clear vision for those people whose eyeballs have elongated is the use of suitable	(A) bifocal lens
Q15. The examples of natural and manmade (artificial) ecosystems are respectively	(C) Lakes and gardens
Q16. Human activities that are affecting the environment are	(B) excessive use of disposable cups and plates.
Q17. Assertion (A): Silver chloride turns grey in sunlight. (R) : Decomposition of silver chloride into silver and chlorine takes place by sunlight.	(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Q18. Assertion (A): The embryo gets nutrition from the mother's blood with the help of a special tissue called the placenta. Reason (R): Placenta is a disc which is embedded in the uterine wall.	(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
Q19. Assertion (A): The pattern of the magnetic field of a solenoid carrying a current is similar to that of a bar magnet. Reason (R): The pattern of the magnetic field around a current-carrying conductor is independent of the shape of the conductor.	(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Q20. Assertion (A): All organisms can make organic compounds like sugar and starch from inorganic substances using the radiant energy of the sun. Reason (R): The organisms which can produce food by photosynthesis are called producers	(C) Assertion (A) is true, but Reason (R) is false.