SECTION - A

Select and write one most appropriate option out of the four
options given for each of the questions 1 - 20 :

1. The emission of brown fumes in the given experimental set-up

is due to
(a) thermal decomposition of lead nitrate which produces brown fumes of
nitrogen dioxide.
(b) thermal decomposition of lead nitrate which produces brown fumes of
lead oxide.
(c) oxidation of lead nitrate forming lead oxide and nitrogen dioxide.
(d) oxidation of lead nitrate forming lead oxide and oxygen.

2. In the experimental setup given below, it is observed that on

passing the gas produced in the reaction in the solution ‘X’ the
solution ‘X’ first turns milky and then colourless.
(a) it turns milky due to carbon dioxide gas liberated in the reaction and
after sometime it becomes colourless due to formation of calcium
carbonate.
(b) it turns milky due to formation of calcium carbonate and on passing
excess of carbon dioxide it becomes colourless due to formation of
calcium hydrogen carbonate which is soluble in water.
(c) it turns milky due to passing of carbon dioxide through it. It turns
colourless as on further passing carbon dioxide, sodium hydrogen
carbonate is formed which is soluble in water.
(d) the carbon dioxide liberated during the reaction turns lime water milky
due to formation of calcium hydrogen carbonate and after some time it
turns colourless due to formation of calcium carbonate which is soluble in
water.

3. The table below has information regarding pH and the nature

(acidic/basic) of four different solutions. Which one of the options
in the table is correct?
(a) Lemon juice - Orange - 3 - Basic
(b) Milk of magnesia - Blue - 10 - Basic
(c) Gastric juice - Red - 6 - Acidic
(d) Pure water - Yellow - 7 - Neutral

4. MnO₂ + x HCl → MnCl₂ + y H₂O + z Cl₂

In order to balance the above chemical equation, the values of x,
y and z respectively are :
(a) 6, 2, 2
(b) 4, 1, 2
(c) 4, 2, 1
(d) 2, 2, 1

5. Select washing soda from the following :

(a) NaHCO₃
(b) Na₂CO₃.5H₂O
(c) Na₂CO₃.10H₂O
(d) NaOH

6. Consider the structures of the three cyclic carbon compounds

A, B and C given below and select the correct option from the
following :
(a) A and C are isomers of hexane and B is benzene.
(b) A is an isomer of hexane, B is benzene and C is an isomer of hexene.
(c) A is a saturated cyclic hydrocarbon and B and C are unsaturated cyclic
hydrocarbons.
(d) A is cyclohexane and B and C are the isomers of benzene.

7. The following diagram shows the electrolytic refining of

copper. Which of the following statements is incorrect description
of the process?
(a) The impure metal from the anode dissolves into the electrolyte.
(b) The pure metal from the electrolyte is deposited on the cathode.
(c) Insoluble impurities settle down at the bottom of the anode.
(d) On passing the current through the electrolyte, the pure metal from
the anode dissolves into the electrolyte.

8. Consider the following statements about small intestine and

select the one which is NOT correct :
(a) The length of the small intestine in animals differs as it depends on the
type of food they eat.
(b) The small intestine is the site of complete digestion of food.
(c) The small intestine receives secretions from liver and pancreas.
(d) The villi of the small intestine absorb water from the unabsorbed food
before it gets removed from the body via the anus.

9. An organism which breaks down the food material outside the

body and then absorbs it is :
(a) a plant parasite, Cuscuta
(b) an animal parasite, Tapeworm
(c) a bacteria, Rhizobium
(d) a fungi, Rhizopus

10. Which of the following metals do not corrode in moist air?

(a) Copper
(b) Iron
(c) Gold
(d) Silver

11. Select from the following the correct statement about tropic
movement in plants :
(a) It is due to stimulus of touch and temperature.
(b) It does not depend upon the direction of stimulus received.
(c) It is observed only in roots and not in stems.
(d) It is a growth related movement.

12. The statement that correctly describes the characteristic(s) of

a gene is :
(a) In individuals of a given species, a specific gene is located on a
particular chromosome.
(b) A gene is not the information source for making proteins in the cell.
(c) Each chromosome has only one gene located all along its length.
(d) All the inherited traits in human beings are not controlled by genes.

13. In domestic electric circuits the wiring with 15 A current

rating is for the electric devices which have :
(a) higher power ratings such as geyser.
(b) lower power ratings such as fan.
(c) metallic bodies and low power ratings.
(d) non-metallic bodies and low power ratings.

14. If four identical resistors, of resistance 8 ohm, are first

connected in series so as to give an effective resistance Rₛ, and
then connected in parallel so as to give an effective resistance Rₚ,
then the ratio Rₛ/Rₚ is :
(a) 32
(b) 2
(c) 0.5
(d) 16

15. The resultant magnetic field at point ‘P’ situated midway

between two parallel wires (placed horizontally) each carrying a
steady current I is :
(a) in the same direction as the current in the wires.
(b) in the vertically upward direction.
(c) zero
(d) in the vertically downward direction.

16. If the current I through a resistor is increased by 100% (at

constant temperature), the increase in power dissipated will be :
(a) 100%
(b) 200%
(c) 300%
(d) 400%

Q. No. 17 to 20 are Assertion – Reason based questions.

These 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) : Genes inherited from the parents decide the
sex of a child.
Reason (R) : X chromosome in a male child is inherited from his
father.

18. Assertion (A) : The colour of aqueous solution of copper

sulphate turns colourless when a piece of lead is added to it.
Reason (R) : Lead is more reactive than copper, and hence
displaces copper from its salt solution.

19. Assertion (A) : The strength of the magnetic field produced at

the centre of a current carrying circular coil increases on
increasing the number of turns in it.
Reason (R) : The current in each circular turn has the same
direction and the magnetic field due to each turn then just adds
up.

20. Assertion (A) : Left atrium receives oxygenated blood from

pulmonary vein.
Reason (R) : Right atrium transfers deoxygenated blood to the
right ventricle, which pumps it to the lungs for oxygenation.
SECTION - B
Q. No. 21 to 26 are very short answer questions.

21. A plant hormone helps in bending of stem towards light.

Name the hormone and explain how is the movement achieved.

22. (a) (i) A compound ‘X’ which is prepared from gypsum has the
property of hardening when mixed with proper quantity of water.
Identify ‘X’ and write its chemical formula.
(ii) State the difference in chemical composition between baking soda and
baking powder.
OR
(b) Write balanced chemical equation for the reaction that occurs when :
(i) blue coloured copper sulphate crystals are heated and
(ii) Sodium hydrogen carbonate is heated during cooking.

23. Name the part of the human excretory system where

nephrons are found. Write the structure and function of
nephrons.

24. Write the constituents of solder alloy. Which property of

solder makes it suitable for welding electrical wires?

25. Why is damage to the ozone layer a cause for concern? What
steps are being taken to limit this damage?

26. (a) A narrow beam XY of white light is passing through a glass

prism ABC as shown in the diagram. Trace it on your answer sheet
and show the path of the emergent beam as observed on the
screen PQ. Name the phenomenon observed and state its cause.
OR
(b) It is observed that the power of an eye to see nearby objects as well as
far off objects diminishes with age.
(i) Give reason for the above statement.
(ii) Name the defect that is likely to arise in the eyes in such a condition.
(iii) Draw a labelled ray diagram to show the type of corrective lens used
for restoring the vision of such an eye.

SECTION - C
Q. No. 27 to 33 are short answer questions.

27. A chemical compound X is used in glass, soap and paper

industries. On treatment with ethanoic acid, it forms salt, water
and carbon dioxide.
(a) Identify X.
(b) How is this compound obtained from brine? Write the equations
involved.
(c) State the number of molecules of water of crystallization present in
compound X.

28. (a) Identify the reducing agent in the following reactions :

(i) 4NH₃ + 5O₂ → 4NO + 6H₂O
(ii) H₂O + F₂ → HF + HOF
(iii) Fe₂O₃ + 3CO → 2Fe + 3CO₂
(iv) 2H₂ + O₂ → 2H₂O
(b) Define a redox reaction in terms of gain or loss of oxygen.

29. A student wants to project the image of a candle flame on a

screen 60 cm in front of a mirror by keeping the candle at a
distance of 15 cm from its pole.
(a) Name the type of mirror used.
(b) Also calculate :
(i) Magnification of the image produced
(ii) Distance between object and its image
(c) Draw a ray diagram to show the image formation.

30. (a) (i) State the role of ATP in cellular respiration.

(ii) What ensures sufficient exchange of gases in plants?
(iii) State the conditions on which the direction of diffusion of gases in
plant depend upon.
OR
(b) (i) What is the internal energy reserve in plants and animals?
(ii) How desert plants perform photosynthesis if their stomata remain
closed during the day?

31. (a) (i) State the rule used to find the force acting on a current
carrying conductor placed in a magnetic field.
(ii) Given below are three diagrams showing entry of an electron in a
magnetic field. Identify the case in which the force will be (1) maximum
and (2) minimum respectively. Give reason for your answer.
OR
(b) (i) Draw the pattern of magnetic field lines of :
(1) a current carrying solenoid
(2) a bar magnet
(ii) List two distinguishing features between the two fields.

32. (a) (i) Why does a kitchen garden called an artificial

ecosystem while a forest is considered to be a natural ecosystem?
(ii) While designing an artificial ecosystem at home, write any two things
to be kept in mind to convert it into a self-sustaining system. Give reason
to justify your answer.
OR
(b) (i) Construct a food chain of four trophic levels comprising the
following : Hawk, snake, plants, rat.
(ii) 20,000 J of energy was transferred by the producers to the organism of
second trophic level. Calculate the amount of energy that will be
transferred by organisms of the third trophic level to the organisms of the
fourth trophic level.

33. A person cannot see distinctly the object placed beyond 5 m

from his eyes. Name the defect of vision the person is suffering
from. Draw a ray diagram to illustrate this defect. List its two
possible causes. Name the lens used for the correction of this
defect.
SECTION - D
Q. No. 34 to 36 are long answer questions.

34. (a) Mention the role of the following organs of human male
reproductive system :
(i) Testis
(ii) Scrotum
(iii) Vas-deferens
(iv) Seminal vesicle
(b) What is Placenta? State its function in a human female.

35. (a) An electric iron consumes energy at a rate of 880 W when

heating is at the maximum rate and 330 W when the heating is at
the minimum. If the source voltage is 220 V, calculate the current
and resistance in each case.
(b) What is heating effect of electric current?
(c) Find an expression for the amount of heat produced when a current
passes through a resistor for some time.

36. (a) A saturated organic compound ‘A’ belongs to the

homologous series of alcohols. On heating ‘A’ with concentrated
sulphuric acid at 443 K, it forms an unsaturated compound ‘B’
with molecular mass 28 u. The compound ‘B’ on addition of one
mole of hydrogen in the presence of Nickel, changes to a
saturated hydrocarbon ‘C’.
(i) Identify A, B and C.
(ii) Write the chemical equations showing the conversion of A into B.
(iii) What happens when compound C undergoes combustion?
(iv) State one industrial application of hydrogenation reaction.
(v) Name the products formed when compound A reacts with sodium.
OR
(b) (i) With the help of diagram, show the formation of micelles, when
soap is applied on oily dirt.
(ii) Take two test tubes X and Y with 10 mL of hard water in each. In test
tube ‘X’, add few drops of soap solution and in test tube ‘Y’ add a few
drops of detergent solution. Shake both the test tubes for the same
period.
(1) In which test tube the formation of foam will be more? Why?
(2) In which test tube is a curdy solid formed? Why?

SECTION - E
Q. 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. In order to trace the inheritance of traits Mendel crossed pea

plants having one contrasting character or a pair of contrasting
characters. When he crossed pea plants having round and yellow
seeds with pea plants having wrinkled and green seeds, he
observed that no plants with wrinkled and green seeds were
obtained in the F₁ generation. When the F₁ generation pea plants
were cross-bred by self-pollination, the F₂ generation had seeds
with different combinations of shape and colour also.
(a) Write any two pairs of contrasting characteristics of pea plant used by
Mendel other than those mentioned above.
(b) Differentiate between dominant and recessive traits.
(c) State the ratio of the combinations observed in the seeds of F₂
generation (in the above case). What do you interpret from this result?
OR
(c) Given below is a cross between a pure violet flowered pea plant (V)
and a pure white flowered pea plant (v). Diagrammatically explain what
type of progeny is obtained in F₁ generation and F₂ generation : Pure
violet flowered plant × Pure white flowered plant.

38. Hold a concave mirror in your hand and direct its reflecting
surface towards the sun. Direct the light reflected by the mirror
on to a white card-board held close to the mirror. Move the card-
board back and forth gradually until you find a bright, sharp spot
of light on the board. This spot of light is the image of the sun on
the sheet of paper; which is also termed as “Principal Focus” of
the concave mirror.
(a) List two applications of concave mirror.
(b) If the distance between the mirror and the principal focus is 15 cm,
find the radius of curvature of the mirror.
(c) Draw a ray diagram to show the type of image formed when an object
is placed between pole and focus of a concave mirror.
OR
(c) An object 10 cm in size is placed at 100 cm in front of a concave
mirror. If its image is formed at the same point where the object is
located, find :
(i) focal length of the mirror, and
(ii) magnification of the image formed with sign as per Cartesian sign
convention.

39. Almost all metals combine with oxygen to form metal oxides.
Metal oxides are generally basic in nature. But some metal oxides
show both basic as well as acidic behaviour. Different metals
show different reactivities towards oxygen. Some react vigorously
while some do not react at all.
(a) What happens when copper is heated in air? (Give the equation of the
reaction involved).
(b) Why are some metal oxides categorized as amphoteric? Give one
example.
(c) Complete the following equations :
(i) Na₂O(s) + H₂O(l) →
(ii) Al₂O₃ + 2 NaOH →
OR
(c) On burning Sulphur in oxygen a colourless gas is produced.
(i) Write chemical equation for the reaction.
(ii) Name the gas formed.
(iii) State the nature of the gas.
(iv) What will be the action of this on a dry litmus paper?

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SECTION A
This section has 20 multiple choice questions (Q.No. 1 - 20). All
questions are compulsory.

1. The number of electrons in the outermost shell of the atom of a

non-metal can be :
(a) 1, 2 or 3
(b) 3, 4 or 5
(c) 5, 6 or 7
(d) 5, 6 or 8

2. Select the correct option(s) in the following table :

Option Natural Sources Acid present

(i) Tamarind Tartaric acid

(ii) Tomato Acetic acid

(iii) Ant sting Oxalic acid

(iv) Nettle sting Methanoic acid

(a) (i) only

(b) (iii) only
(c) (i) and (iv)
(d) (i), (ii) and (iv)
3. Among the following, the metal with lowest density is :
(a) Lithium
(b) Lead
(c) Magnesium
(d) Aluminium

4. Which of the following is an example of endothermic process ?

(a) Formation of slaked lime
(b) Decomposition of vegetable matter into compost
(c) Dissolution of ammonium chloride in water
(d) Digestion of food in our body

5. In order to balance the following chemical equation, the values

of the coefficients xx and yy respectively are :

x Pb(NO3)2→Heat2 PbO+y NO2+O2xPb(NO3)2Heat2PbO+yNO2+O2

(a) 2, 4
(b) 2, 2
(c) 2, 3
(d) 4, 2

6. When zinc reacts with sodium hydroxide, the product formed is

:
(a) Sodium oxide
(b) Sodium zincate
(c) Zinc hydroxide
(d) Zinc oxide

7. Select the correct option from the following :

Parent
Salt Parent acid Nature of salt
base

(a) Sodium acetate CH3COOHCH3COOH NaOH Neutral

(b) Sodium carbonate H2CO3H2CO3 NaOH Basic

 Parent
Salt Parent acid Nature of salt
base

(c) Sodium chloride HCl NaOH Acidic

(d) Sodium nitrate HNO3HNO3 NaOH Acidic

8. For verifying Ohm’s law, we design an electric circuit diagram

in which we show the arrangement of different circuit
components. We find that with respect to the resistor, the :
(a) ammeter is connected in parallel and the voltmeter in series.
(b) ammeter is connected in series and the voltmeter in parallel.
(c) ammeter and voltmeter are both connected in series.
(d) ammeter and voltmeter are both connected in parallel.

9. An object is placed in front of a convex mirror at infinity.

According to the New Cartesian Sign Convention, the sign of the
focal length and the sign of the image distance in this case are
respectively :
(a) +,−+,−
(b) −,+−,+
(c) −,−−,−
(d) +,++,+

10. When an X' bearing sperm fertilises the egg, the resulting
zygote has the following combination of chromosomes :
(a) 44 + XX
(b) 44 + XY
(c) 22 + XX
(d) 22 + XY

11. Sphincter muscles are present at the exit of :

(a) Stomach and small intestine
(b) Stomach and anus
(c) Small intestine and large intestine
(d) Oesophagus and stomach
12. In the following diagram, identify the cells through which
massive amounts of gaseous exchange takes place for
photosynthesis :

(a) I
(b) IV
(c) III
(d) II

13. During vigorous exercise, the occurrence of cramps in the

outer muscles of an athlete is due to the conversion of pyruvate
to :
(a) Glucose
(b) Ethanol
(c) Lactic acid
(d) Lactose

14. Plants which bear unisexual flowers are :

(a) Mustard and Papaya
(b) Hibiscus and Watermelon
(c) Mustard and Hibiscus
(d) Watermelon and Papaya
15. A positron enters a uniform magnetic field at right angles to it
as shown. The direction of force experienced by the positron will
be :

(a) to the right

(b) to the left
(c) into the page
(d) out of the page

16. In a resistive circuit if the current is increased to two times,

the percentage change in the amount of heat dissipated in the
circuit would be :
(a) 400%
(b) 300%
(c) 200%
(d) 100%

For Questions number 17 to 20, two statements are given — one

labelled as Assertion (A) and the other labelled as Reason (R).
Select the correct answer to these questions from the codes (a),
(b), (c) and (d) as given below.

(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the
correct explanation of the Assertion (A).
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the
correct explanation of the Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Assertion (A) is false, but Reason (R) is true.
17. Assertion (A): Magnetic field lines do not intersect each other.
Reason (R): Magnetic field lines are imaginary lines, the tangent to which
at any point gives the direction of the field at that point.

18. Assertion (A): Sodium oxide is an amphoteric oxide.

Reason (R): Metal oxides which react with both acids as well as bases
are known as amphoteric oxides.

19. Assertion (A): The angle through which a ray of light bends on
passing through a prism is called the angle of deviation.
Reason (R): The peculiar shape of a prism makes the emergent ray bend
at an angle to the direction of the incident ray.

20. Assertion (A): When a bacterium divides into two, and the
resultant two bacteria divide again, the four bacteria produced
would be almost similar.
Reason (R): DNA copying involves small inaccuracies in the reproduction
process.

SECTION B

21. V – I graph for two conducting wires A and B are as shown. If

both wires are of the same length and same diameter, which of
the two is made of a material of high resistivity ? Give reasons to
justify your answer.
22. State the role of the following in the process of digestion :
(a) Bile juice and bile salts
(b) Pancreatic enzymes

23. (a) What is observed when aqueous solutions of potassium

iodide and lead nitrate are mixed together ? Name the type of
reaction and write the chemical equation for the reaction that
occurs.

OR

(b) When copper powder is heated in a watch glass, a black substance is

formed.
(i) Why is this black substance formed ? Name it.
(ii) How can this black substance be reversed to its original form ?

24. Mendel crossed a pure tall pea plant (TT) with a pure short
pea plant (tt) and obtained all tall plants in F1F1 generation.
(a) What is the gene combination present in the plants
of F1F1 generation?
(b) Give reason why only tall plants are observed in F1F1 progeny.
(c) What will be the ratio of the plants obtained in the F2F2 generation
when F1F1 plants are self-pollinated?

25. (a) When and where does a rainbow appear in the sky ? Draw
a labelled ray diagram to show its formation.

OR

(b) What is scattering of light ? Why does the clear sky appear blue ?

26. “Ozone, although a deadly poison, performs an essential

function for the earth and its inhabitants.” Explain.

SECTION C
27. (a) Define oxidation.
(b) Identify the oxidising agent in the following reactions and balance the
chemical equations:
(i) Pb3O4+HCl⟶PbCl2+Cl2+H2OPb3O4+HCl⟶PbCl2+Cl2+H2O
(ii) MnO2+Al⟶Mn+Al2O3MnO2+Al⟶Mn+Al2O3

28. (a) Copper reacts with a moist gas ‘A’ in the air and slowly
loses its shiny brown surface. It turns green. Identify ‘A’ and the
substance of the green coating formed on the surface of copper.
(b) How is copper obtained from its sulphide ore ? Write the chemical
equations for the reaction involved in its extraction.

29. (a) (i) What is meant by excretion ?

(ii) Name the organ that connects the kidneys with the urinary bladder.
State its function.
(iii) List two factors on which the amount of water reabsorbed depends.

OR

(b) (i) In the human respiratory system, name the following :

(I) Part where air is filtered by fine hairs and mucus lining
(II) Part which separates chest cavity from abdominal cavity
(III) Balloon like structures where exchange of gases takes place
(IV) The two large air passages that lead from trachea to the lungs

(ii) List any two characteristics of lungs which make it an efficient

respiratory surface.

30. (a) A student has focussed the image of an object of height 3

cm on a white screen using a concave mirror of focal length 12
cm. If the distance of the object from the mirror is 18 cm, find the
values of the following :
(i) Distance of the image from the mirror
(ii) Height of the image

OR
(b) Define power of a lens. The focal length of a lens is −10 cm−10cm.
Write the nature of the lens and find its power. If an object is placed at a
distance of 20 cm from the optical centre of this lens, according to the
New Cartesian Sign Convention, what will be the sign of magnification in
this case?

31. Explain how some harmful chemicals enter our bodies through
the food chain. Why is the concentration of these harmful
chemicals found to be maximum in human beings?

32. (a) List two factors on which the magnitude of magnetic field
produced by a current carrying straight conductor depends.
(b) State the rule which determines the direction of magnetic field in the
above case.
(c) Draw the pattern of magnetic field lines produced in this case.

33. Name the hormone released and the gland which secretes it
in human beings during scary situations. How does the body
respond to enable it to deal with the situation?

SECTION D

34. (a) (i) List three points of difference between nervous and
hormonal mechanisms for control and coordination in animals.
(ii) How are auxins related with the bending of plant shoot towards
unidirectional light? Explain.

OR

(b) (i) Name the disorder which a person is likely to suffer from due to the
following :
(I) Over-secretion of growth hormone
(II) Deficiency of oestrogen in females
(III) Less secretion of thyroxine
Also name the gland that secretes each of the hormones mentioned
above.

(ii) How is the timing and amount of hormone released regulated ? Explain
with the help of an example.

**35. (a) An acid ‘X’ and an alcohol ‘Y’ react with each other in the
presence of an acid catalyst to form a sweet smelling substance ‘Z’.
Identify ‘X’, ‘Y’ and ‘Z’. Write the chemical equation for the reaction
involved and name it. The substance ‘Z’ on treatment with sodium
hydroxide produces back the alcohol ‘Y’ and sodium ethanoate. Write the
chemical equation for the reaction involved and name it, giving
justification for the name.

OR

(b) (i) Name the simplest saturated hydrocarbon. Draw its electron dot
structure. Which type of bonds exist in this compound ?
(ii) Name any two mixtures of the carbon compound used as a fuel in daily
life, of which the above mentioned compound is an important component.
(iii) In which homologous series of carbon compounds can this compound
be placed ? Write the general formula of the series.
(iv) Which type of flame is produced on burning it ?

36. (a) Draw a ray diagram for showing the convergence of a

parallel beam of light by a concave mirror and mark the positions
of pole and the centre of curvature in it.
(b) An object 4 cm in size is placed at 25 cm in front of a concave mirror of
focal length 15 cm. At what distance from the mirror should a screen be
placed in order to obtain a sharp image ? Find the nature and size of the
image.
(c) List any two uses of a concave mirror.

SECTION E
The following questions are source-based/case-based questions.
Read the case carefully and answer the questions that follow.

37. The teacher while conducting practicals in the laboratory

divided the students into three groups and gave them various
solutions to find out their pH and classify them into acidic, basic
and neutral solutions.

Group A – Lemon juice, vinegar, colourless aerated drink

Group B – Tomato juice, coffee, ginger juice
Group C – Sodium hydroxide, sodium chloride, lime water

(a) For the solutions provided, which group is/are likely to have pH value
(i) less than 7, and (ii) greater than 7 ?
(b) List two ways of determining pH of a solution.
(c) Explain, why the sour substances such as lemon juice are effective in
cleaning the tarnished copper vessels.

OR

(c) “pH has great importance in our daily life.” Justify this statement by
giving two examples.

38. All the reproductive methods of living organisms are broadly

categorized into two types : 1. Asexual reproduction, and 2.
Sexual reproduction.

Asexual reproduction involves the participation of a single parent without

the formation of gametes, fertilisation and transfer of genetic material.
This method is a common means of rapidly increasing offsprings under
favourable conditions.

(a) Name the type of fission that occurs in Leishmania and Plasmodium.
(b) Write one advantage of sexual mode of reproduction over asexual
reproduction.
(c) Give reasons why :
(i) Colonies of yeast fail to multiply in water but multiply in sugar solution.
(ii) Rhizopus individuals do not grow on a dry slice of bread.

OR

(c) Name the filamentous structures a student could identify when he

collected water from a pond that appeared dark green. How do these
organisms multiply ? Explain.

39. Consider the following electrical circuit diagram in which nine

ΩΩ each are connected as shown. If the
identical resistors of 3
reading of the ammeter A1A1 is 1 ampere, answer the following
questions:

(a) What is the relationship between the readings of A1A1 and A3A3? Give
reasons for your answer.
(b) What is the relationship between the readings of A2A2 and A3A3?
(c) Determine the reading of the voltmeter V1V1.

OR

(c) Find the total resistance of the circuit.