CBSE(NCERT) GRADE 10 SCIENCE 2025 COMPARTMENT SET1

The chemical reaction of solid calcium oxide with water is :

In which one of the following decomposition reactions energy is released ?

Juice of tamarind turns blue litmus to red. It is because of the presence of an acid called :

Which one of the following oxides reacts with HCl as well as NaOH to form corresponding salt and water ?

Consider the following cases/reactions : (i) CuSO$_4$ + Al $→$ (ii) CaSO$_4$ + Mg $→$ (iii) FeSO$_4$ + Pb $→$ (iv) ZnSO$_4$ + Ca $→$ The cases/reactions in which new products will form are :

A hydrocarbon which is different from the other three is :

One formula unit of which one of the following salts has seven molecules of water of crystallisation ?

Select the correct statements from the following about the human heart : (i) Right atrium receives oxygenated blood from lungs through pulmonary artery. (ii) Right atrium receives deoxygenated blood through vena cava from upper and lower body. (iii) Left atrium transfers oxygenated blood to left ventricle which sends it to various parts of the body. (iv) Left atrium transfers oxygenated blood to aorta which sends it to various parts of the body.

When digestion is complete in the human alimentary canal, then (i) carbohydrates, (ii) fats and (iii) proteins are finally converted into which of the following ?

In the human alimentary canal, when the process of digestion is completed, the (i) carbohydrates, (ii) fats, and (iii) proteins get converted respectively into :

Which is the gland that is found in the head region near the brain ?

A gland which does not occur as a pair in the body of human beings is :

The part of a seed which is a source of food during its germination is :

A cross made between two pea plants produces 50% tall and 50% short pea plants. The gene combination of the parental pea plants must be :

An optical device always forms images of magnification $m = +1$. This device is :

Select the correct statements from the following in the context of the human eye : (i) Most of the refraction of light rays entering the eye occurs at the crystalline lens. (ii) The diameter of the eye ball is about $2.3\ \text{cm}$. (iii) Iris is a dark muscular diaphragm which controls the size of the pupil. (iv) While focusing on the objects at different distances, the distance between the lens and the retina is adjusted by the ciliary muscles.

Four wires a, b, c and d are made of the same materials. If ‘l’ denotes length and ‘r’ denotes radius, then the wire which offers least resistance to the flow of electric current has length and radius respectively as :

Select from the following, a food chain in which the organism of the second trophic level is missing :

Assertion (A): Sodium sulphate is a neutral salt. Reason (R): Sodium sulphate is a salt formed by a strong acid and a strong base.

Assertion (A): Ozone layer protects the surface of the earth from the harmful ultraviolet radiations. Reason (R): Chlorofluorocarbons (CFCs) are responsible for the depletion of the ozone layer present at the higher levels of the atmosphere.

Assertion (A): The rate of breathing in aquatic organisms is faster than that in terrestrial organisms. Reason (R): The amount of oxygen dissolved in pond/river water is comparatively higher than the amount of oxygen present in air.

Assertion (A): The magnification of the virtual images produced by concave mirrors is always more than +1. Reason (R): The virtual images formed by concave mirrors are erect and magnified.

When magnesium ribbon is burnt in oxygen, an ash of white colour is produced. Name the type of reaction giving justification for your answer. Write the balanced chemical equation for the reaction that occurs.

Photosynthesis takes place in the leaves of a plant and the food prepared by the leaves reaches other parts of the plant. Name and explain the process involved in the phenomenon.

(a) Where are auxins synthesised? How are they related to phototropism?

(b) There is a hormone which regulates carbohydrates, proteins and fat metabolism in the human body. Name the hormone and the gland which secretes it. State the importance of iodised salt in our diet.

List four characteristics of the images formed by convex mirrors.

State Ohm’s law. Give reason why the shape of voltage versus current $(V-I)$ graph for a conductor should be a straight line passing through the origin.

In a straight conductor, the current is flowing vertically downwards. State the pattern of the magnetic field lines around the conductor. Name the rule which helps us to determine the direction of the magnetic field lines in this case.

Give one chemical equation each for the chemical reaction in which the following changes occur (Mention the change in temperature/colour and/or the compound precipated with the equation) : (a) Change in temperature (b) Change in colour (c) Formation of precipitate

What is chlor-alkali process? Write chemical equation for the reaction involved in this process. Name the electrode at which (i) chlorine gas, and (ii) hydrogen gas is given off.

(a) (i) Name the movement that occurs all along the gut in the human digestive system. How do these movements help in the digestion of food? (ii) Where is bile juice stored in the human body? List its two roles.

(b) Give reason for each of the following : (i) Alveoli in lungs are richly supplied with blood capillaries. (ii) Respiratory pigment in the blood takes up oxygen and not carbon dioxide gas. (iii) During anaerobic respiration, a 3-carbon molecule is formed as an end product instead of $CO_2$ in human beings.

(a) (i) Name the movement that occurs all along the gut in the human digestive system. How do these movements help in the digestion of food? (ii) Where is bile juice stored in the human body ? List its two roles. OR (b) Give reason for each of the following: (i) Alveoli in lungs are richly supplied with blood capillaries. (ii) Respiratory pigment in the blood takes up oxygen and not carbon dioxide gas. (iii) During anaerobic respiration, a 3-carbon molecule is formed as an end product instead of CO$_2$ in human beings.

(a) List two constituents of Central Nervous System (CNS). How are these components protected?

(b) Write two limitations of the use of electrical impulses.

(a) List two constituents of Central Nervous System (CNS). How are these components protected ? (b) Write two limitations of the use of electrical impulses.

Define the term ‘power of accommodation’ of human eye. Write the name of the part of eye which plays a major role in this process and explain what happens when the human eye focuses (i) on nearby objects, and (ii) on distant objects.

(a) What is an electric fuse ? Explain its role in a domestic circuit. (b) An electric heater of rating 2 kW; 220 V is to be operated in a room having fuse rating of 5 A. What is likely to happen when the heater is switched on ? Justify your answer with necessary calculations.

Consider the following food chain: Plants → Deer → Lion In this food chain, state the impact of removing all the organisms of the second trophic level (i.e., Deer) on the organisms of the first and the third trophic levels ? Will the impact be the same for the organisms in the third trophic level if they were part of the food web of the ecosystem ? Justify your answer.

(a) Write the chemical name and the formula of a carbon compound having two carbon atoms in its molecule and belongs to a family of functional group –OH. What happens when this compound reacts with the following ? (Give chemical equation and the name of main product formed in each case) (i) Excess conc. sulphuric acid (H$_2$SO$_4$) at 443 K (ii) Ethanoic acid in the presence of an acid (iii) Acidified potassium dichromate (iv) Sodium metal OR

This compound reacts with the following? Give chemical equation and the name of the main product formed in each case: (i) Excess conc. sulphuric acid ($\mathrm{H_2SO_4}$) at 443 K (ii) Ethanoic acid in the presence of an acid (iii) Acidified potassium dichromate (iv) Sodium metal

(a) (i) List two roles of each of the following in human reproductive system: (I) Seminal vesicles and Prostate glands (II) Oviduct (III) Testis (ii) What happens in a human female when (I) fertilisation takes place, and (II) an egg is not fertilised? OR (b) (i) Name and state the reproductive process taking place in (I) Plasmodium, and (II) Leishmania. (ii) Name three techniques/devices used by human females to avoid pregnancy. Also mention the side effects of each.

(a) (i) If $R_s$ and $R_p$ respectively are the total resistances of the series and parallel combinations of the three resistors of resistances $R_1$, $R_2$ and $R_3$, then write the relationships among (I) $R_s$, $R_1$, $R_2$ and $R_3$ and (II) $R_p$, $R_1$, $R_2$ and $R_3$. (ii) An electric oven operates on the mains voltage of 220 V. This oven consumes 2.2 kWh of electrical energy in one hour. Calculate: (I) power rating of the oven, (II) current drawn by the oven, and (III) resistance of the oven when in operation. OR (b) (i) Define the term electric power. Express it in terms of potential difference ($V$) and resistance ($R$). (ii) The resistance of a metal wire of length 6 m is 120 $\Omega$. If the area of cross-section of the wire is $4 \times 10^{-7}\,\mathrm{m^2}$, calculate the electrical resistivity of the material of the wire. How would the resistivity be affected if this wire is gradually stretched so that its length is doubled? Justify your answer.

(i) If $R_s$ and $R_p$ are the resistances of the series and parallel combinations of the three resistors of resistances $R_1$, $R_2$ and $R_3$, then write the relationships among (I) $R_s$, $R_1$, $R_2$ and $R_3$ and (II) $R_p$, $R_1$, $R_2$ and $R_3$. (ii) An electric oven operates on the mains voltage of 220 V. This oven consumes 2.2 kWh of electrical energy in one hour. Calculate: (I) power rating of the oven, (II) current drawn by the oven, and (III) resistance of the oven when in operation.

(b) (i) Define the term electric power. Express it in terms of potential difference ($V$) and resistance ($R$). (ii) The resistance of a metal wire of length 6 m is 120 $\Omega$. If the area of cross-section of the wire is $4 \times 10^{-7}\,\text{m}^2$, calculate the electrical resistivity of the material of the wire. How would the resistivity be affected if this wire is gradually stretched so that its length is doubled? Justify your answer.

The metals produced by various reduction processes are generally not very pure. They contain impurities of other metals and non-metals which must be removed to obtain pure metals. The most commonly used method for purifying metals is "electrolytic refining" by which metals like gold, silver, zinc, copper, etc. are refined. (a) In the electrolytic refining of silver, what are the anode and cathode made of? (b) Write the name and chemical formula of the electrolyte used in this process.

The metals produced by various reduction processes are generally not very pure. They contain impurities of other metals and non-metals which must be removed to obtain pure metals. The most widely used process for refining metals such as gold, silver, zinc, copper, etc. is electrolytic refining. (a) What is the cathode and anode made of in the refining of silver by this process ?

(b) Name the electrolyte used in this process and write its chemical formula.

State the laws of reflection of light.

Define the term 'Principal axis of a concave mirror.'

Write the path of the following light rays after reflection from a concave mirror: (I) A ray of light moving parallel to the principal axis of a concave mirror. (II) A ray incident obliquely to the principal axis towards the pole of the concave mirror making angle $\theta$.

An object is placed at 18 cm in front of a concave mirror of focal length 12 cm. Use mirror formula to determine the position of the image.