Science Board Sample Paper 2024-2025 English Medium Class 10 Question Paper Solution

Identify ‘p’, ‘q’ and ‘r’ in the following balanced reaction:

\[\ce{p Pb(NO3)_{2(s)} ->[Heat] q PbO_{(s)} + r NO_{2(g)} + O_{2(g)}}\]

2, 2, 4

2, 4, 2

2, 4, 4

4, 2, 2

Match column I with column II and select the correct option using the given codes.

a – (ii), b – (i), c – (iii), d – (iv)

a – (iii), b – (i), c – (iv), d – (ii)

a – (iv), b – (ii), c – (iii), d – (i)

a – (iii), b – (ii), c – (i), d – (iv)

The solution in the given figure is likely to be:

HNO₃

C₂H₅OH

H₂SO₄

CO₂ in water

An aqueous solution ‘A’ turns the phenolphthalein solution pink. On addition of an aqueous solution ‘B’ to ‘A’, the pink colour disappears. Which of the following statement is true for the solutions ‘A’ and ‘B’.

A is strongly basic and B is a weak base.

A is strongly acidic and B is a weak acid.

A has a pH greater than 7 and B has a pH less than 7.

A has a pH less than 7 and B has a pH greater than 7.

When 50 g of lead powder is added to 300 ml of blue copper sulphate solution, after a few hours, the solution becomes colourless. This is an example of ______.

Combination reaction

Decomposition reaction

Displacement reaction

Double displacement reaction

The electronic configuration of three elements X, Y and Z are X - 2, 8, 7; Y - 2, 8, 2; and Z - 2, 8.

Y and Z are metals.

Y and X are non-metals.

X is a non-metal and Y is a metal.

Y is a non-metal and Z is a metal.

Which of the following is an endothermic reaction?

Burning of candle.

Cooking of food.

Decomposition of Vegetable matter.

Reaction of Sodium with air.

During cellular oxidation of Glucose, ATP is produced along with formation of other products in this reaction. Which of the following events is associated with production of maximum ATP molecules per molecule of Glucose during this process? Synthesis of:

ethanol in yeast.

lactic acid in muscle cells.

carbon dioxide in yeast cells.

carbon dioxide in human cells.

During which of the following stages of the circulation of blood in a normal human being, the oxygenated blood is pumped to all parts of the body?

contraction of the left atrium

contraction of left ventricle

relaxation of the right atrium

relaxation of the right ventricle

Which of the following adaptations in herbivores helps in the digestion of cellulose?

Longer large intestine

Smaller large intestine

Smaller small intestine

Longer small intestine

There was a cerebellar dysfunction in a patient. Which of the following activities will get disturbed in this patient as a result of this?

Salivation

Hunger control

Posture and balance

Regulation of blood pressure

In snails individuals can begin life as male and depending on environmental conditions they can become female as they grow. This is because ______.

male snails have dominant genetic makeup.

female snails have dominant genetic makeup.

expression of sex chromosomes can change in a snail’s life time.

sex is not genetically determined in snails.

In the following cases, a ray is incident on a concave mirror. In which case is the angle of incidence equal to zero?

A ray parallel to the principal axis.

A ray passing through the centre of curvature and incident obliquely.

A ray passing through the principal focus and incident obliquely.

A ray incident obliquely to the principal axis, at the pole of the mirror.

Choose the correct option for the colour of rays for A and B.

Identify the incorrect statement:

‘The energy available to the producers is maximum’ because ______.

It is the first trophic level which absorbs 1% of light energy directly from the source.

It utilizes the most of the chemical energy for its own respiration, growth, reproduction, movement etc.

It utilizes 10% of light energy and transfers the rest to the next trophic level.

It transfers only 10% of light energy to the next trophic level.

Which of the following is not a role of decomposers in the ecosystem?

Natural replenishment of soil.

Enrichment of oxygen in the atmosphere.

Waste decomposition.

Break-down of dead remains.

Assertion (A): On adding dil. HCl to a test tube containing a substance ‘X’, a colourless gas is produced which gives a pop sound when a burning match stick is brought near it.

Reason (R): In this reaction metal ‘X’ is displaced by Hydrogen.

Both A and R are true, and R is the correct explanation of A.

Both A and R are true, and R is not the correct explanation of A.

A is true but R is false.

A is false but R is true.

Assertion (A): The number of chromosomes in a cell and in a germ cell is not the same in any species.

Reason (R): When 2 germ cells combine they restore the normal number of chromosomes in a species.

Both A and R are true, and R is the correct explanation of A.

Both A and R are true, and R is not the correct explanation of A.

A is true but R is false.

A is false but R is true.

Assertion (A): A convex mirror always forms an image behind it and the image formed is virtual.

Reason (R): According to the sign convention, the focal length of a convex mirror is positive.

Both A and R are true, and R is the correct explanation of A.

Both A and R are true, and R is not the correct explanation of A.

A is true but R is false.

A is false but R is true.

Assertion (A): If the lions are removed from a food chain it will not affect the food chain, however if the plants are removed from a food chain it will disturb the ecosystem.

Reason (R): Plants are producers who can make food using sunlight, while lions are consumers.

Both A and R are true, and R is the correct explanation of A.

Both A and R are true, and R is not the correct explanation of A.

A is true but R is false.

A is false but R is true.

Identify the type of the following reaction, stating the reason for your answer.

\[\ce{Fe2O3 + 2Al -> Al2O3 + 2Fe + heat}\]

Identify the type of the following reaction, stating the reason for your answer.

\[\ce{Pb (NO3)2 + 2KI -> PbI2 (↓) + 2KNO3}\]

Differentiate between alveoli and nephron on the basis of the following points:

List the steps for the synthesis of glucose by the plants. What special feature is found in desert plants related to this process?

Explain the role of the following enzyme in the process of digestion of food in humans:

Salivary amylase

Explain the role of the following enzyme in the process of digestion of food in humans:

Pepsin

Explain the role of the following enzyme in the process of digestion of food in humans:

Trypsin

Explain the role of the following enzyme in the process of digestion of food in humans:

Lipase

The above figure shows the formation of an image by a lens shown by a thick line.

Analyse the figure and answer the following questions.

1. What is the type of lens used?
2. What is the nature of the image?
3. If the image is formed at a distance of 30 cm from the lens and the image is twice the size of the object, then where is the object placed?

The electric circuit (above figure) in a clothes dryer contains two heaters X and Y in parallel. The above figure shows the circuit connected to a 230 V power supply. When both switches are closed, the current in X is 3.5 A.

Analyse the circuit given above and answer the following questions.

1. Calculate the power developed in heater X.
2. If the resistance of X is double that of Y, calculate the current in heater Y.

The above figure shows two resistors X and Y connected in series to a battery. The power dissipated for this combination is P₁. When these resistors are connected in parallel to the same battery, then the power dissipated is given by P₂. Find out the ratio `P_1/P_2`.

The cartoon below addresses a growing concern:

What impact will the process shown in the image have on humans if they occupy the last trophic level? Explain.

Anirudh took two metal oxides: aluminium oxide and magnesium oxide, as shown in the pictures given below. But he forgot to label them. How will you guide/help Anirudh to identify the oxides and label them?

In an activity, Aishu was given two substances: Copper Sulphide (Cu₂S) and Copper Oxide (Cu₂O) to obtain copper from these compounds. She was able to extract Copper successfully. Illustrate with the help of chemical equations how Aishu might have completed the activity.

\[\ce{NaCl + H2O + CO2 ^ + NH3 ^ ->}\]
\[\ce{X + Y ->[\Delta]}\]
\[\ce{Z + H2O + CO2 ^ ->[10 H2O]}\]
\[\ce{Q}\]

1. In the given series of reactions, name the compounds X and Z.
2. Which type of reaction is X to Z?
3. You are given 3 unknown solutions A, B, and C with pH values of 6, 8 and 9.5 respectively. In which solution will the maximum number of hydronium ions be present? Arrange the given samples in the increasing order of H⁺ ion concentration.

Comment on the following statement:

Bee sting is treated with baking soda paste, whereas wasp sting is treated with dilute vinegar.

Comment on the following statement:

Farmers treat soil with quicklime when tilling.

Comment on the following statement:

Ancient sculptures and marble structures are conserved by treating them with certain chemicals.

Water is used by the leaves of the plants for photosynthesis, but rather than watering the leaves, we water the plant through the soil. How does this water reach the leaves of the plant?

1. In a family of four individuals, the father possessed long ears and the mother possessed short ears. If the parents had pure dominant and recessive traits, respectively, then calculate the ratio of the genetic makeup of the F2 generation. Show a suitable cross.
2. If the father had short ears and the mother had long ears, explain what effect it will have on the ratio of genetic makeup in the F2 generation.

What is the fundamental difference between hypermetropia and myopia in terms of the optical experience of a person?

The diagram below shows a special case of an eye defect.

1. What is the defect that is shown in the figure?
2. State one cause for such a defect?
3. Explain with reason if a concave lens can be used to correct the defect.

1. State the relationship between the resistance R of a wire to its length l and cross-sectional area A. Use the mathematical symbols to arrive at the final formula.
2. Using the formula, define the resistivity of a material.

Mona was doing an experiment with a magnetic compass and a straight current-carrying wire. She observed that as she moved the compass away from the current-carrying wire, the deflection of the compass needle reduced.

1. Explain why the deflection of the compass needle reduced as Mona moved away the compass needle from the current-carrying wire.
2. Mention one thing that could have changed in the circuit of the wire that could increase the deflection of the needle.
3. Explain with reason what will be the direction of the magnetic field associated with the wire for the case described by the above figure.

“Keerthi thinks that substitution reactions occur in saturated hydrocarbons; on the contrary, Krishi thinks it occur in unsaturated hydrocarbons.” Justify with valid reasoning whose thinking is correct.

“Methane and Propane and their Isomers are used as fuels.” Comment.

Draw the electron dot structure of the immediate lower homologue of Propane.

Give any two characteristics of a homologous series.

A mixture of oxygen and ethyne is burnt for welding. Can you predict why a mixture of ethyne and air is not used?

‘A’ & ‘B’ are sodium salts of long-chain carboxylic acid and long-chain Sulphonic acid respectively. Which one of A or B will you prefer as a cleansing agent while using underground water (hand pump water)? Give the reason for your answer.

Elaborate on the process of cleansing action. Illustrate micelle with the help of labelled diagram.

Write the chemical equation of the preparation of soap from an ester CH₃COOCH₃. What is the name of this process?

The image below shows a banana plant which is growing with the help of suckers. These suckers are small plant stem outgrowths which can be separated from the main plant and planted separately and they will grow into a new plant subsequently.

1. Give the name and type of reproduction that is shown in the image above.
2. List two advantages the farmer will have on using the type of reproduction mentioned above.
3. The above plant produces male flowers. Explain how this plant will be involved in the process of pollination.
4. Why is the offspring of this banana plant not absolutely identical to its parent plant?

The image below shows a developing fetus in the mother's womb. The developing fetus is connected to the placenta by means of umbilical cord. The Umbilical vein and artery run inside the umbilical cord.

1. Name two substances that move through the blood vessels.
2. If the placenta has less villi, how will it affect the baby’s growth? 
3. Name the region where the embryo develops inside the female body. Explain how this region is adapted for nourishing the baby.
4. Some of the fetal cells fall off into the amniotic fluid and can be collected by careful procedure. The cells were screened and found to contain XY chromosomes. 
   1. What is the sex of the foetus?
   2. How is this prenatal sex determination misused?

The above circuit is a part of an electrical device. Use the information given in the question to calculate the following.

1. Potential Difference across R₂.
2. Value of the resistance R₂.
3. Value of resistance R₁.

As shown in the figure above, A and B are two lamps. Lamp A is rated at 12 V, 24 W. Lamp B is rated at 6.0 V. When lamp B operates at its rated voltage, the current in it is 3.0 A. The values of R₁ and R₂ are chosen so that both lamps operate at their rated voltages.

Based on the information given, answer the following.

1. Calculate the current in Lamp A.
2. State and give reason for the reading of the voltmeter.
3. Calculate the resistance of R₂.
4. Find the value of the resistance R₁.

1. \[\ce{A + H2O ->[ELECTROLYSIS] \underset{SODA}{\underset{CAUSTIC}{X}} + \underset{ANODE}{Y ^} + \underset{CATHODE}{Z ^}}\]

2. \[\ce{\underset{MOLTEN}{A} ->[ELECTROLYSIS] \underset{CATHODE}{M} + \underset{ANODE}{Y ^}}\]

3. \[\ce{M + CH3COOH -> P + Z ^}\]

4. \[\ce{CH3COOH + Q ->[Conc.][H2SO4] R}\]

5. \[\ce{R + X -> P + Q}\]

1. Derive the names of A, Y, Z, M, P & R.
2. Improvise an activity to test Z.
   OR
3. Name the process in which compounds X, Y & Z are formed from A. Justify your response.

Mohan and Rohit observed that shoots of a plant growing in shade bend towards the sunlight. Whereas, leaves of ‘Touch me not’ plant fold and droop soon after touching. They were curious to know how these movements occur in plants.

   A. Shoots of a plant bending towards light

                  B. Folding of leaves Touch me not plant

In order to help them understand the movements in the plants, answer the following questions:

1. What causes the bending of shoots in the plants as shown in figure A?
   OR
2. What causes the folding of the leaves in ‘Touch me not’ plant as shown in figure B?
3. Compare the movement of growth of the pollen tube towards ovule with the movements shown in part A of the above figure.
4. Compare the movement shown in figure B with the movement of body parts in the animals.

The above image is that of a reflecting telescope. Reflecting telescopes revolutionised our ways of looking into the sky. They employ mirrors to gather and focus light rather than relying solely on lenses as in their refracting counterparts. These telescopes utilise precisely shaped and polished mirrors to capture incoming light and reflect it to a focal point, where it forms an image for observation.

1. What kind of image of the star is seen by the observer at the eyepiece?
2. What kind of mirror is used in this reflecting telescope?
3. Explain with reason what kind of optical device (type of lens or mirror) that is used at the eyepiece.
   OR
4. What is the role of the plane mirror in the telescope?