CBSE 10 Science Set 3 Answer Key 2025 Unofficial (Available)

1

Consider the following chemical equation : pAl + q H₂O → r Al₂ O₃ + SH₂

To balance this chemical equation, the values of 'p', 'a, "r' and 's' must be respectively : 

 (C) 2,3,1,3

2

Which of the given option represents a family of salts? 

(B) K₂SO₄ , NA₂SO₄ , CaSO₄

3

The most common method of extraction of metals from their oxide ores iS :

(A) Reduction with carbon

4

Given below are the structures of some hydrocarbons. Select the two structures which are related to each other from the given options

C (ii) and (iii)

5

Choose the incorrect statement about the common reaction used in hydrogenation of vegetable oils.

(D) It is an addition reaction which occurs in the presence of an acid catalyst.

6

Match Column 1 with Column2

D

7

The part of the brain which maintains the posture and balance of the body is :

(C) Cerebellum

8

The plant hormone present in greater concentration in the areas of rapidly dividing cells is :

(B) Cytokinins

9

Select a pair of bisexual flowers from the following :

(B) Hibiscus and mustard

10

The gastric glands present in the wall of the stomach release :

(C) Mucus and Pepsin

11

11: Absolute refractive index of water and glass is 4/3 and 3/2 respectively. If the speed of light in glass is 2 x 108 m/s, the speed of light in water is :

(A) 9/4 ms

12

When a beam of white light passes through a region of very fine dust particles, the colour of light that scatters the most in that region is :

(C) Blue

13

 A wire of length 'l' is gradually stretched so that its length increases to 3l. If its original resistance is R, then its new resistance will be:

(C) 9R

14

Which one of the following statements is not true about a bar magnet ?

(D)The direction of magnetic field lines inside a bar magnet is from its north pole to its south pole.

15

The strength of magnetic field produced inside a long straight current carrying solenoid does not depend upon :

(B) Direction of current flowing through the solenoid

16

Other than the abiotic components, which of the given biotic components are not required to make an aquarium with small herbivorous fishes a self-sustaining system ?

D (ii) and (IV)

17

Assertion (A) : Hydrogen gas is not evolved when a metal reacts with nitric acid.

Reason (R) : Nitric acid is a strong reducing agent and reduces the hydrogen produced in the reaction to water.

C

18

(A) : In our actions of writing or talking, our nervous system communicates with the muscles.

Reason (R) : Cranial nerves and spinal nerves form the peripheral nervous system.

B

19

Assertion (A) : Magnetic field lines around a bar magnet never intersect each other.

Reason (R) : Magnetic field produced by a bar magnet is a quantity that has both magnitude and direction.

B

20

Assertion (A) Use of jute bags for shopping reduces pollution 

Reason (R) : Jute is biodegradable and its bag may be reused as and when needed.

A

English

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CBSE Class 10 Social Science Answer Key 2025 Unofficial (Available)