BHARATIYA VIDYA BHAVAN, KOCHI

FIRST MODEL EXAMINATION

2023-2024

Std : X General Science( 086) Max. Marks : 80

Time : 3hrs

SET - I
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. Answers 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
Select and write the most appropriate option out of the four options given for each of the
questions 1 - 20. There is no negative mark for incorrect response.
Q.Nos. Questions Marks

1 Which of the following statements about the given reaction are correct? 1
3Fe(s) + 4H₂O(g) → Fe₃O₄ (s) + 4H₂ (g)
(i) Hydrogen is getting oxidised.
(ii) Water is getting reduced.
(iii) Fe is acting as a reducing agent.
(iv) Fe₃O₄ is acting as oxidizing agent.
a) i and iii
b) ii and iii
c) ii and iv
d) i and ii

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2 The reaction in which two compounds exchange their ions to form new compounds is 1
called
a) displacement reaction
b) redox reaction
c) double displacement reaction
d) decomposition reaction

3 The chlor-alkali process is used for the preparation of: 1

a) washing soda
b) sodium hydroxide
c) sodium chloride
d) baking soda

4 Rohan has aqueous solutions of three salts, sodium carbonate, potassium 1

sulphate and ammonium chloride in three test tubes. The test tubes are not
labelled.
On checking, he finds the pH of the solutions to be 4.6, 7.0 and 10.9.
Which of the following correctly matches the salts with their respective pH?
pH 10.9 pH 7 pH 4.6

A sodium carbonate potassium sulphate ammonium chloride

B ammonium chloride sodium carbonate potassium sulphate

C potassium sulphate ammonium chloride sodium carbonate

D ammonium chloride potassium sulphate sodium carbonate

a) A
b) B
c) C
d) D
5 What happens when magnesium is treated with hot water? 1
(i) It reacts violently with water .
(ii) It reacts less violently with water .
(iii) It does not react with water.
(iv) Bubbles of hydrogen gas stick to the surface of metal.
a) (i)and (iv)
b) (ii) and (iii)
c) (iii) and (iv)
d) (ii) and (iv)

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6 Aluminum oxide (Al₂O₃) is known to exhibit amphoteric behaviour, acting as both an 1
acid and a base. When Al₂O₃ reacts with sodium hydroxide (NaOH), which of the
following products is formed?
a) Al(OH)₃ + H₂O
b) Al(OH)₃ + Na₂O
c) NaAlO₂ + H₂
d) NaAlO₂ + H₂O

7 Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among 1
the following alloys contain non-metal as one of its constituents?
a) Brass
b) Bronze
c) Steel
d) Amalgam

8 Identify the unicellular organism that has a definite shape and the intake of food is 1
through a specific spot.
a) Amoeba
b) Yeast
c) Paramoecium
d) Lice

9 All information from our environment is detected by specialised tips of some nerve 1
cells. Identify these specialised tips of nerve cells where information is acquired.
a) Neuron
b) Receptors
c) Axon
d) Dendrite

10 Identify the advantages of the method that makes it possible for the propagation of 1
plants such as banana, orange etc that have lost the capacity to produce seeds.
i) All plants produced are genetically dissimilar enough to the parent plant.
ii) Can bear flowers and fruits slower than those produced from seeds.
iii) Can bear flowers and fruits earlier than those produced from seeds
iv) All plants produced are genetically similar enough to the parent plant.

a) both ii and iii are correct statements

b) both ii and iv are correct statements
c) both iii and iv are correct statements
d) both i and ii are correct statements

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11 What do the progeny of a tall plant with round seeds(TTRR) and a short plant with 1
wrinkled-seeds (ttrr) look like in F1 generation?
a) They are all short and have round seeds.
b) They are all tall and have round seeds.
c) They are all tall and have wrinkled seeds.
d) They are all short and have wrinkled seeds.

12 Diverse organisms produce energy from food in different ways – some use oxygen to 1
break-down glucose completely and some use other pathways that do not involve
oxygen. Which of the following is the first step in both cases?
a) Break-down of glucose, a six-carbon molecule, into a three-carbon molecule
called pyruvate.
b) Break-down of glucose, a six-carbon molecule, into a three-carbon molecule
called lactic acid.
c) Break-down of glucose, a six-carbon molecule, into a two-carbon molecule
called ethanol.
d) Break-down of glucose, a six-carbon molecule, into carbon dioxide and water.

13 Large number of thin stripes of black paint are made on the surface of a convex lens of 1
focal length 20 cm to catch the image of a white horse. The image will be
(a) a zebra of black stripes
(b) a horse of black stripes
(c) a horse of less brightness
(d) a zebra of less brightness

14 Which option given below justifies the blue color of the sky? 1
(a) Blue color is scattered least by the atmosphere
(b) Blue has high wavelength, so the intensity of scattering will be less
(c) Blue has low wavelength, so the intensity of scattering will be more
(d) The white light disperses into seven colors, only blue enters the atmosphere

15 “X” at the higher levels of the atmosphere is a product of “Y” radiation acting on 1
oxygen (O2 ) molecules. “X” and “Y” respectively referred here in the given equation
are:

a) CFCs ; Ozone
b) Ozone ; CFCs
c) Ozone ; UV rays
d) UV rays; Diatomic oxygen

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16 If a grasshopper is eaten by a frog, then the energy transfer will be from 1
a) producer to decomposer
b) producer to primary consumer
c) primary consumer to secondary consumer
d) secondary consumer to primary consumer

Question No. 17 to 20 consist of two statements – Assertion (A) and Reason (R).
Answer these questions 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, but 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 (A) :During the electrolysis of water, the volume of gas obtained at 1
cathode is more than the volume of gas obtained at anode.
Reason (R) : Hydrogen is obtained at cathode and oxygen is obtained at anode during
the electrolysis of water.

18 Assertion(A): DNA copying is necessary during reproduction 1

Reason (R) : DNA copying leads to the transmission of characters from parents to
offspring.

19 Assertion(A) : The strength of the magnetic field in a circular coil of a wire depends 1
on the current flowing through the coil.
Reason (R) : The strength of the magnetic field in a circular coil of a wire depends on
the number of turns of the wire in the coil.

20 Assertion(A): Trophic levels are formed by only plants. 1

Reason (R) : Food chains and webs are formed due to linked organisms on the basis
of their nutrition.

Section-B
Question No. 21 to 26 are very short answer questions
21 Write balanced chemical equation for the following: 2
i) Silver chloride is exposed to sunlight.
ii) Lead is added to copper (II) chloride solution.

22 What is meant by pollination? Differentiate between the two modes of pollination in 2

flowering plants.

23 Compare alveoli in the lungs and nephrons in the kidneys with respect to their 2
structure and functioning.
OR

How do the products of photosynthesis move from leaves, where they are formed to
other parts of the plant?

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24 The refractive indices of glass and water with respect to air are 3/2 and 4/3 2
respectively. If the speed of light in glass is 2 × 108 m/s, find the speed of light in
water.

25 What is a solenoid? How does a solenoid act as a magnet? 2

OR
Name and state the rule to determine the direction of
(i) the magnetic field produced around a straight current carrying conductor
(ii) the force experienced by a current carrying straight conductor kept in a magnetic
field.

26 A food web is given below, observe the figure and answer the questions given below. 2

(a) Identify the primary consumer/s in the food web.

(b) If all the foxes are killed due to a disease, how will the food web be affected?

Section-C
Question No. 27 to 33 are short answer questions
27 You are provided with 90 mL of distilled water and 10 mL of concentrated sulphuric 3
acid to prepare dilute sulphuric acid.
(i) What is the correct way of preparing dilute sulphuric acid? Give reason.
(ii) How will the concentration of H3O + ions change on dilution?
(iii) Why does an aqueous solution of an acid conduct electricity?

28 A metal 'M' is found in nature as its carbonate. It is used in the galvanization of iron. 3
Identify 'M' and name its ore. How will you convert this ore into free metal ?
OR
An element M with electronic configuration 2,8,1 combines with oxygen to form its
oxide Z.
(i) Write the formula of the oxide ‘Z’ formed.
(ii) Identify the type of bond in compound ‘Z’.
(iii)Show the formation of the compound ‘Z’ by the transfer of electrons.
(iv)Compound 'Z' has high melting point and boiling point .Why?

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29 a) Our brain and spinal cord are known as the most delicate organs. How are the 3
human brain and spinal cord protected?
b) Electrical impulses are an excellent means of transmission of stimuli in multicellular
organisms but there are limitations.Justify the statement by citing two reasons.

30 In sexually reproducing organisms the number of chromosomes in the progeny is 3

maintained over generations.Explain.

31 A student cannot clearly see a chart hanging on a wall placed at a distance of 3 m from 3
him.
a) Name the defect of vision he is suffering from.
b) List two possible causes of the defect.
c) Draw a ray diagram to show how this defect may be corrected using a lens of
appropriate focal length.

32 In the given circuit, A, B, C, and D are four lamps connected to a battery of 60 V.

Analyze the circuit to answer the following questions when the keys are closed.
a) What type of combination are the lamps arranged in the above circuit?
b) Which lamp glows the brightest? Why?
c) Find out the total resistance of the circuit.

33 (a) “Two magnetic field lines never intersect each other.” Why?
(b) An electric oven of 1.5 kW is operated in a domestic circuit (220V) that has a fuse
of current rating 5A.What result do you expect in this case? Explain. 3

Section-D
Question No. 34 to 36 are long answer questions
34 i) Draw the electron dot structure of methane by showing sharing of electrons between 5
carbon and hydrogen atoms.
ii) What are structural isomers? Draw any two structural isomers of hexane.
iii) List two reasons for carbon forming a large number of compounds.
OR
The formulae of four organic compounds are given below:
A – C2H4 , B – CH3COOH , C – C2H5OH , D – C2H6
i) Which one of these compounds A, B, C, or D is an unsaturated hydrocarbon?
ii) What is the name of the functional group present in compound B ?
iii) Which of the above compounds when heated at 443K in the presence of conc.
H2SO4 forms ethene as the major product? What is the role played by conc.

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 H2SO4 in this reaction? Also, write the chemical equation involved.
iv) Give a chemical equation when B and C react with each other in presence of conc.
H2SO4.Name the major product formed and mention one of its important uses.

35 a) The embryo gets nutrition from the mother’s blood with the help of a special tissue 5
labelled as ‘X’. Identify ‘X’. Explain its structure and function.

b) Give a suitable reason for the following situation:

i) A tube grows out of the pollen grain and travels through the style to reach the ovary.
ii) Binary fission in Leishmania , occurs in a definite orientation.
iii) Prenatal sex determination has been prohibited by law.
OR
A survey was conducted by a group of students, as a part of raising awareness about
the impact of blood sugar level on the health of people. For that they conducted a
fasting blood sugar test.The graph given below is plotted based on the data collected.
(Normal fasting blood sugar level is less than 100 mg/dL).

Observe the graph and answer the following questions.

a) Identify the person who is having high blood sugar level. Which hormone
deficiency is responsible for this?

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 b) Name the disease he is suffering from and suggest a treatment to supplement
the deficient hormone.
c) How is the timing and amount of this hormone secretion regulated?

36 Riya wants to obtain an erect image of an object using a concave mirror of 12 cm focal 5
length.
a) What should be the range of distance of the object from the mirror?
b) Write the nature and size of the image she is likely to observe.
c) Draw a ray diagram to show the image formation in this case.
d) Where will the image be formed if the object is placed 24 cm in front of the
mirror?
OR
A convex lens has a focal length of 10 cm. At what distance from the lens should the
object be placed so that it forms a real and inverted image 20 cm away from the lens?
What would be the size of the image formed if the object is 2 cm high? With the help
of a ray diagram show the formation of the image by the lens in this case?

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 series of organic compounds having the same functional group, with similar or 1+1+2
almost identical chemical characteristics in which all the members can be represented
by the same general formula and the two consecutive members of the series differ by
–CH2 group or 14 mass unit in their molecular formula is called a homologous series.
For example, all the members of the alcohol family can be represented by the general
formula,C n H 2n + 1 OH where n may have the values 1, 2, 3,... etc. The various
members of a particular homologous series are called homologous. The physical
properties such as density, melting point, boiling point, solubility, etc. of the members
of a homologous series show almost regular variation in ascending or descending the
series.
(i) Write the name and formula of the second member of ketones.
(ii) Draw the structure of butanal.
(iii) Write the molecular formula of the lower and higher members of homologous
series C4H10. and determine the total number of covalent bonds present in C4H10.
OR
How will you convert alkene to alkanes ? Explain with the example of ethene.

38 The following table gives an idea about the number of each plant type obtained in the 1+1+2
F2 generation of a cross between pea plants with yellow coloured seeds and green
coloured seeds.

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 No.of plants Yellow coloured seed Green coloured seed

1016 762 254

On the basis of above data answer the following questions.
a) Identify the dominant character.
b) How does the parental plant with yellow coloured seed and the plant in
the F1 generation differ in their alleles?
c) Depict the cross to show the progeny in the F₂ generation.
OR
Write the genotypic ratio of the progeny in the F₂ generation. What explanation
would you give for the expression of characters in the offspring which were
hidden in the parental plant?

39 Several resistors may be combined to form a network. The combination should have 1+1+2
two end points to connect it with a battery or other circuit elements. When the
resistances are connected in series, the current in each resistance is the same but the
potential difference is different in each resistor. When the resistances are connected in
parallel, the potential difference across each resistance is the same but the current is
different in each resistor.

i) The I - V characteristics of two wires each of resistance R are connected first in

series and then in parallel. Which of the following is correct?

(a) A denotes a parallel combination.

(b) A denotes series combination
(c) B denotes a parallel combination.
(d) both b and c

ii) The equivalent resistance of two resistors r1 and r2, when connected in series is R1
and when they are connected in parallel is R2. Then find the ratio of R1/R2

2
1 1+ 2 ( 1+ 2) 1 2
( ) 2
(b) 1 2
(c) 1 2
(d) 2 1+2 2

iii) Three resistors are connected as shown in the figure below. Find the equivalent
resistance and the total current flowing through the circuit .

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 OR

iii) Three resistors are connected as shown in the figure below. Find the equivalent
resistance and the total current flowing through the circuit.

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