G R CONVENT SR. SEC.

SCHOOL
NYAY KHAND I INDIRAPURAM
Academic Session-2024-25
Subject: Science (086)
PRE BOARD EXAMINATION
Class- X
Date: M.M.70
Time: 3.00 Hours. Teacher’s Sign:
General Instructions:
i. This question paper consists of 39 questions in 5 sections.

ii. All questions are compulsory. However, an internal choice is provided in some

questions. A student is expected to attempt only one of these questions.

iii. Section A consists of 20 objective type questions carrying 1 mark each.

iv. Section B consists of 6 Very Short questions carrying 02 marks each. Answers to

these questions should be in the range of 30 to 50 words.

v. Section C consists of 7 Short Answer type questions carrying 03 marks each.

Answers to these questions should be in the range of 50 to 80 words.

vi. Section D consists of 3 Long Answer type questions carrying 05 marks each.
Answer to these questions should be in the range of 80 to 120 words.

vii. Section E consists of 3 source-based/case-based units of assessment of 04 marks

each with sub-parts.

SECTION - A
1.Identify ‘p’, ‘q’ and ‘r’ in the following balanced reaction

p Pb (NO3)2(s) ---- q PbO(s) + r NO2(g) + O2(g)

A. 2,2,4. B. 2,4,2 C. 2,4,4 D. 4,2,2

2.The solution in the given figure is likely to be

A. HNO3
B. C2H5OH
C. H2SO4
D. CO2 in water
3. 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. A is strongly basic and B is a weak base.

B. A is strongly acidic and B is a weak acid.

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

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

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

and Z – 2, 8

A. Y and Z are metals

B. Y and X are non-metals

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

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

5. When 50g 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
A. Combination reaction
B. Decomposition reaction
C. Displacement reaction
D. Double displacement reactio

6. Which of the following is an endothermic reaction?

A. Burning of candle.
B . Cooking of food.
C. Decomposition of Vegetable matter.
D. Reaction of Sodium with a metal.

8 Which of the following method/s are useful to prevent fertilisation even

when ovulation occurs?

P) surgical blocking of the fallopian tube Q) copper-T

R) oral pills S) condom

(a) only P (b) only Q and R

(c) only P, Q and S (d) only Q, R and S

9.Patient X was suffering from a pancreatic condition due to which the

pancreas was not functioning adequately.

 Which of the following is a doctor likely to suggest to such an individual?

(a) including a large amount of protein in the diet (b) eating a diet with low-fat

content

(c) eating only carbohydrates (d) including only liquid food

10.Walking in a straight line and riding a bicycle are the activities which are possible
due to a part of the brain.Choose the correct location and name of this part from
the given pairs.
(a) Fore brain - Cerebrum (b) Mid Brain --Hypohathalmus
(c) Hind brain --Cerebellum (d) Hind Brain --Medulla
11.Select from the following a plant hormone which promotes cell division.
(a) Gibberellins (b) Auxins
(c) Abscissic Acid (d) Cytokinins
12.Parts of a flower which attracts insects for pollination are
(a) Petals and Sepals (b) Anther and Stigma
(c) Petals only (d) Sepals only
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15. The food chain will be more advantageous in terms of energy if it has
(a) 2 trophic levels (b) 3 trophic levels
(c) 4 trophic levels (d) 5 trophic levels

16.The action of which among the following is crucial to the formation of

ozone?

(a) humans (b) sunlight

(c) carbon dioxide (d) chlorofluorocarbons

Question No. 17 to 20 consist of two statements – Assertion (A) and Reason

(R). Answer thesequestions selecting the appropriate option given below:

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

B. Both A and R are true and R is not the correct explanation of A.
C. A is true but R is false.
D. A is False but R is true.

17. Assertion : 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 : In this reaction metal ‘X’ is displaced by Hydrogen.

18. Assertion : Variations always provide a survival advantage to an

Reasons :Variations can be caused due to incorrect DNA copying.

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20. Assertion: The waste we generate daily may be biodegradable or non-
biodegradable

Reason : The waste generated,if not disposed off properly may cause serious

environmental problems.

SECTION - B
21. Identify the type of each of the following reactions stating the reason
for your answers.
A. Fe2O3 + 2Al → Al2O3 + 2Fe + heat
B. Pb (NO3)2 + 2KI → PbI2( )+ 2KNO3
22. Where are auxins synthesised? How do they promote phototropism?
23List any two pairs of visible contrasting characters of garden pea
plants used by Mendel for his experiments stating that the dominant
and recessive characters in each pair.
Or
In human beings , the probability of getting a male or a female child is
50%.Explain with the help of a flow diagram only.
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25.Physics
26.What are decomposers? List two consequences of their absence in an
ecosystem.
SECTION - C
27. A. 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.
B. Give reasons for the following
i Certain metals are used for making cooking utensils.
ii Hydrogen gas does not evolve when certain metals except Mg & Mn react with
nitric acid
28. A. 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.

B.Comment on the following statements:

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

ii. Farmers treat soil with quicklime before tilling.

29.In animals, hormones can be secreted by one organ and can act on multiple

organs. Justify this statement by explaining the effect of a single animal

hormone on three organs.

30.If two pea plants having round and green seeds (RRGg) are crossed, identify

the percentage of the following with respect to the F1 generation:

(a) gametes having both the round and yellow seed traits

(b) offspring having the same genotype as the parents

(c) offspring having the same phenotype as the parents

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SECTION - D
34. (I) A and ‘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.

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

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

35. (a) Name the two types f pollination and differentiate between them.
(b) Explain the post fertilisation changes occur in the ovary of a flower.

(c) In germinating seed Name the parts which

(i) give rise to the future shoot

(ii) give rise to the root system

(iii) stores food

Or

(a) Certain specialised cells in animals called stem cells have the ability to

divide and differentiate into different cell types. This helps in the replacement

of a damaged organ.

Name and explain two methods of asexual reproduction that are similar to

stem cells and occur mostly in multicellular organisms.

(b) Identify TWO pairs of reproductive organs in males and females that are

functionally similar to each other. Justify.

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SECTION - E
Question No. 37 to 39 are case-based/data -based questions with 2 to 3 short sub-
parts.

Internal choice is provided in one of these sub-parts

37. A. Distinguish between ethanol and ethanoic acid experimentally.

B. Give the IUPAC name of the first member of Alkene which is formed by
addition of conc. Sulphuric acid to it. Illustrate the change with the help of a chemical
equation.

“All combustion reactions are oxidation but all oxidation reactions are not
combustion” justify
38.Human digestive system is a tube running from mouth to anus.Its main function is
to breakdown complex molecules present in the food which cannot be absorbed as
such into smaller molecules.These molecules are absorbed across the walls of the
tube and the absorbed food reaches each and every cell of the body where it is
utilised for obtaining energy.

(a) Name the glands present in the buccal cavity and write the components of food
on which the secretion of these glands act upon.

(b) Two organs have a sphincter muscle at their exit. Name them.

(c) What will happen if:

(i) Mucus is not secreted by the gastric glands.

(ii) Villi are absent in the small intestine.

Or

(c) ‘Bile juice does not contain any enzyme,yet it has important roles in
digestion.’Justify the statement.

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