Question bank

Chapter-1   Introduction to Chemistry
Q-1

Four different models of the atom are shown - A, B, C and D. In the table given below, write the name assigned to each model, name of the scientist and the year in which the model was proposed.
Q-2 The Sun is a huge, fiery ball of gaseous matter, the two most abundant gases being hydrogen (70%) and helium (28%). The hydrogen atoms, through a series of chemical reactions, fuse or combine to form helium atoms. This fusion reaction releases energy in the form of heat and light.
(a) Hydrogen gas is present on the Sun but is absent in the Earth's atmosphere. Explain.
(b) Would it be correct to say that life on Earth is powered by chemical reactions taking place in the core of the Sun? List the reasons to support your answer.
(c) What is the importance of the solar energy to plants?
(d) What climate change is likely to occur if the nuclear fusion reaction on the Sun were to stop?
Q-3 Rocks and Minerals on the Earth's crust are a rich source of raw materials. Many metals can be extracted from the ores found in rocks.
(a) Name a metal extracted and used by the ancient people to make tools and weapons .
(b) Name a metal used by them for making jewellery.
(c) Name the metals that constitute brass.
(d) Name the metals that are contained in bronze.
(e) What is the name or term that describes materials like brass and bronze which are a mixture of two or more metals?
Q-4

Cakes and pastries are decorated with colourful icing. Find out the names of two chemicals that are used as edible colouring matter.
Q-5 Many useful substances occur in nature. Raw materials from a variety of sources can be converted into new and useful products by chemical changes. For example:
(a) Coal which is a naturally occurring mineral in the Earth's crust, burns in oxygen present in the air to form carbon dioxide.

(b) Green plants use carbon dioxide and water in the presence of sunlight (radiant energy) to prepare food in the form of carbohydrates (glucose) 

(c) When plants respire, the oxygen of the air breaks down the glucose into carbon dioxide and water vapour. These are released into the atmosphere. The energy produced during this process is used by the plant to carry out various metabolic activities.
Q-6 Fill in the blanks using only the terms Combustion, respiration, photosynthesis
(a) Burning of coal is an example of ___________ .
(b) The carbon dioxide formed during and is used up _________ __________ by green plants during ___________ .
(c) Plants give out oxygen during ___________ and carbon dioxide is given out during ____________ .
(d) Glucose and oxygen are the raw materials used in _____________ .
(e) Carbon dioxide and water are the raw materials used in
Q-7 An experiment was set up as shown.
(a) Mention two differences that are seen at the end of the experiment.

(b) Give an explanation for the changes mentioned in (i) 

(c) Name the gas present in B.
(d) Name the scientist who was the first to perform the experiment shown here.

(e) If a leafy twig was placed in the jar along with the burning candle, and the apparatus is placed in sunlight, what are you likely to observe? Explain

Q-8 In the formation of rust, four atoms of iron combine with six atoms of oxygen.
(a) How many atoms are there to the left of the arrow?
(b) How many atoms are there to the right of the arrow?
(c) From the above reaction can it be said that matter is conserved?

(d) Is iron an element or a compound? Justify your answer.

(e) Name the first scientist who gave a scientific explanation of the atom. 

Q-9 Answer the following questions.
(a) "We are surrounded by chemicals". Give three examples to support this statement.
(b) If you were to go on a mountain trek, would you prefer to carry cotton clothes or synthetic clothes in your backpack? Explain your choice.
(c) Make a list of five items made of plastic that you use on a daily basis. What feature of plastic makes it such a useful material?
(d) List three uses of synthetic rubber.
Q-10 Name two natural fibres of:
(a) Plant origin
(b) Animal origin
Multiple Choice Questions
Q-1 This gas is not present in Earth's atmosphere:

(i)

Helium

(ii)

Hydrogen

(iii)

Nitrogen

(iv)

Carbon dioxide
Q-2 This is the most abundant element in the Earth's crust:

(i)

Copper

(ii)

Gold

(iii)

Aluminium

(iv)

Iron

Q-3 Carbonates are metals combined with carbon and:

(i)

Oxygen

(ii)

Nitrogen

(iii)

Sulphur

(iv)

Hydrogen 

Q-4 This is not an element:

(i)

Oxygen

(ii)

Nitrogen

(iii)

Water

(iv)

Hydrogen
Q-5 Metals that occur in rocks are called:

(i)

Alloys

(ii)

Ores

(iii)

Compounds

(iv)

Elements
Q-6 This metal could be extracted only after electricity was discovered:

(i)

Gold

(ii)

Iron

(iii)

Sodium

(iv)

Copper
Q-7 The four element theory of matter was put forth by:

(i)

Socrates

(ii)

Plato

(iii)

Aristotle

(iv)

Robert Boyle
Q-8 Which of the following is NOT part of the scientific method?

(i)

Making a guess

(ii)

Making an observation

(iii)

Conducting an experiment

(iv)

Forming a hypothesis
Q-9 Which statement is NOT part of Dalton's postulates?

(i)

Atoms are divisible

(ii)

All atoms of an element are identical.

(iii)

Atoms are indivisible

(iv)

Atoms cannot be created or destroyed
Q-10 The Plum Pudding model of the atom was put forth by:

(i)

Ernest Rutherford

(ii)

Niels Bohr

(iii)

Robert Boyle

(iv)

J.J Thomson

Q-11 Which of these is NOT a synthetic fibre:

(i)

Cotton

(ii)

Nylon

(iii)

Polyester

(iv)

Rayon
Q-12 Which of these fibres is sourced from animals?

(i)

Cotton

(ii)

Jute

(iii)

Silk

(iv)

None of these
Q-13 Which of these is NOT a fossil fuel?

(i)

Coal

(ii)

Natural Gas

(iii)

Petroleum

(iv)

None of these
Q-14 Which of these is NOT a man-made material?

(i)

Plastic

(ii)

Detergents

(iii)

Paint and dyes

(iv)

None of these
Q-15 Carbon dioxide was first prepared by:

(i)

John Mayow

(ii)

Joseph Black

(iii)

Lavoisier

(iv)

Robert Boyle
Chapter-2   Fundamentals of Matter
Q-1 State whether the following statements are true or false:
(a) Solids are highly compressible.
(b) Gases can be stored in open vessels.
(c) The atoms in solids are very far apart.
(d) The force of attraction between the molecules of gases is very weak.
(e) Methane is a gas.
(f) Mercury has a concave meniscus.
(g) Plastic is a bad conductor of heat and electricity.
Q-2 Give one term for the properties stated below. Also give one example for each property.
(a) Substance can be beaten into sheets.
(b) Substance allows heat to flow through it.
(c) Substance dissolves in water.
(d) Substance changes its shape when a force is applied to it. It does not regain its original shape when the force is removed.
(e) Substance changes its shape when a force is applied to it. It regains its original shape when the force is removed .
(f) Substance can be drawn into wires.
Q-3 Study the illustration given below and answer the questions that follow:
(a) Give the number of the substance that exists in the solid state.
(b) Give the number of the substance that exists in the liquid state.

(c) Suggest a method by which the solid can be converted into a liquid.

(d) Suggest a method by which the liquid can be converted into a solid.

(e) State the term use to describe the phenomenon in which the liquid changes into: a. its solid state b. its vapour state
Q-4 Name:
(a) A gas that has the smell of rotten eggs.
(b) A gas that is greenish-yellow in colour.
(c) A metal that is reddish in colour.
(d) A solid that is crystalline.
(e) A substance that is a heat insulator.
(f) A solid that is amorphous.
(g) A gas that has a pungent odour.
(h) The force of attraction between like molecules of the same substance.
(i) The force of attraction between unlike molecules of the different substances.
Multiple Choice Questions
Q-1 Which of the following is NOT matter?

(i)

Spoon

(ii)

Mercury

(iii)

Heat

(iv)

Carbon dioxide
Q-2 Which of the following is NOT a subatomic particle?

(i)

Neutron

(ii)

Proton

(iii)

Nucleus

(iv)

Electron
Q-3 Which of the following is NOT a characteristic of solids?

(i)

Rigid

(ii)

Compressible

(iii)

Fixed shape

(iv)

Fixed volume
Q-4 Which of the following is NOT a characteristic of liquids?

(i)

Fluid

(ii)

Fixed shape

(iii)

Fixed volume

(iv)

One free surface
Q-5 Which of the following is NOT a characteristic of gases?

(i)

Loose, random arrangement of particles

(ii)

Highly compressible

(iii)

Mingle with particles of other gases

(iv)

Very rigid
Q-6 Which of the following statement is False for gases?

(i)

Strong attractive force between particles

(ii)

Large gaps between particles

(iii)

Can be stored only in closed containers

(iv)

No fixed shape and volume
Q-7 Which of these is the effect of heat on matter?

(i)

Change in state

(ii)

Change in size

(iii)

Chemical change

(iv)

All of these
Q-8 Which of the following is True for matter?

(i)

Matter expands when cooled

(ii)

Matter contracts when cooled

(iii)

Matter expands when heated

(iv)

b and c are true
Q-9 The conversion of matter from solid to gaseous state is called:

(i)

Condensation

(ii)

Sublimation

(iii)

Deposition

(iv)

Evaporation
Q-10 Which of these are amorphous solids?

(i)

Talcum powder

(ii)

Plastic

(iii)

Flour dough

(iv)

All of these
Q-11 Which is true with regard to the odour of ammonia gas?

(i)

Odourless

(ii)

Fragrant smell

(iii)

Pungent odour

(iv)

None of these
Q-12 If a solid can be drawn into wires, it is said to be:

(i)

Malleable

(ii)

Ductile

(iii)

Elastic

(iv)

None of these
Q-13 Which of these will not allow heat or electricity to pass through them?

(i)

Wood

(ii)

Plastic

(iii)

Rubber

(iv)

All of these
Q-14 In water, the molecules pull together into a spherical shape due to the force of:

(i)

Gravity

(ii)

Cohesion

(iii)

Adhesion

(iv)

Magnetism
Q-15 The meniscus of mercury is:

(i)

Concave

(ii)

Convex

(iii)

Horizontal

(iv)

None of these
Chapter-3   Elements, Compounds and Mixtures
Q-1 Define:
(a) An element
(b) A compound
(c) A mixture
Q-2 Name:
(a) The most abundant element in the Earth's crust.
(b) A liquid metal.
(c) The first element that was ever formed.
(d) The most abundant element in the air.
(e) A liquid non-metallic element.
(f) The substance formed when iron combines with oxygen.
(g) A metalloid.
(h) The first element to become known to man.
(i) A non-metal that is a good conductor of heat and electricity.
(j) A compound containing nitrogen and hydrogen.
Q-3 Answer the following questions.
(a) Distinguish between an atom and a molecule.
(b) Write the symbols of the following elements: Carbon, oxygen, nitrogen, zinc, lead, iron, copper, hydrogen
(c) Write the formula of the following compounds: Water, ammonia, carbon dioxide, sodium chloride, hydrogen chloride
Q-4 Classify the following as metals, nonmetals and metalloids
(a) Copper
(b) Bromine
(c) Helium
(d) Zinc
(e) Silicon
(f) Lead
(g) Sulphur
(h) Boron
(i) Potassium
(j) Mercury
Q-5 Classify the following as elements, compounds and mixtures.
(a) Petrol
(b) Milk
(c) Sodium
(d) Sugar
(e) Oxygen
(f) Salt solution
(g) Carbon dioxide
(h) Chalk
(i) Potassium
(j) Water
Q-6 Give two examples of each:
(a) Homogeneous mixture
(b) Heterogeneous mixture
Q-7 State whether the following statements are true or false:
(a) All solutions are homogeneous.
(b) All solid mixtures are heterogeneous.
(c) Formation of compound involves absorption or evolution of energy.
(d) Components of a mixture can be separated by simple physical methods.
(e) Molecules combine to form atoms.
Multiple Choice Questions
Q-1 Which of the following is a liquid metal?

(i)

Bromine

(ii)

Mercury

(iii)

Iodine

(iv)

Neon
Q-2 There are ___________ gaseous elements known to us.

(i)

9

(ii)

10

(iii)

11

(iv)

12
Q-3 There are _________ liquid elements known to us.

(i)

6

(ii)

3

(iii)

4

(iv)

5
Q-4 Which of the following is NOT a metalloid?

(i)

Arsenic

(ii)

Boron

(iii)

Carbon

(iv)

Silicon
Q-5 Which of the following is NOT a characteristic of non-metals?

(i)

High melting point and boiling point

(ii)

Low melting point and boiling point

(iii)

Poor conductors of heat and electricity

(iv)

Non-malleable and non-ductile
Q-6 Which of the following statement is False for metals?

(i)

They have low densities

(ii)

They have high densities

(iii)

Generally solids at room temperature

(iv)

Malleable and ductile
Q-7 Silicon becomes a good conductor of electricity when is added to it :

(i)

Boron

(ii)

Mercury

(iii)

Carbon

(iv)

Sulphur
Q-8 __________ is a form of carbon that conducts electricity:

(i)

Coal

(ii)

Graphite

(iii)

Diamond

(iv)

None of these
Q-9 A water molecule contains hydrogen and oxygen in the ratio:

(i)

1:2

(ii)

1: 1

(iii)

2:1

(iv)

2:2
Q-10 When iron is heated with sulphur, the compound formed is:

(i)

Iron sulphite

(ii)

Iron sulphide

(iii)

Iron sulphate

(iv)

None of these
Q-11 The colour of sulphur is:

(i)

Brown

(ii)

Red

(iii)

Yellow

(iv)

Pink
Q-12 Hydrogen burns with a __________ flame:

(i)

Yellow

(ii)

Blue

(iii)

Orange

(iv)

Green
Q-13 Which of the following is a characteristic of water?

(i)

It is non combustible

(ii)

It is a non supporter of combustion

(iii)

It boils at 100°C and freezes at 0°C

(iv)

All of these
Q-14 The nitrogen molecule is made up of nitrogen atoms:

(i)

1

(ii)

2

(iii)

3

(iv)

4
Q-15 The symbol of sodium is:

(i)

S

(ii)

So

(iii)

Na

(iv)

None of these
Chapter-4   Separation of Mixtures
Q-1 Answer the following questions.
(a) How does a chemist define separation?
(b) Why does a chemist need to work with pure chemicals?
(c) Why is it important to drink pure, clean water?
(d) What is the principle underlying separation techniques?
(b) Why is it important to drink pure, clean water?
Q-2 Some common daily methods of separation are listed below. Select an appropriate method used from the list given. Filtration, Straining, Sieving, Handpicking, Winnowing, Sifting, Washing, Boiling
(a) Removing tiny stones from rice.
(b) Separating light particles like husk from rice.
(c) Separating soluble particles from rice and lentils.
(d) Separating fine flour from coarse flour.
(e) Separating tea leaves from tea.
(f) Making shrikhand by removing water from the curd (yogurt).
(g) Making paneer (cottage cheese) by separating the whey from the curdled milk.
(h) Separating the seed covering of peanuts form the nuts.
Q-3 Explain the following terms:
(a) Food adulteration
(b) Sedimentation
(c) Sublimation
Q-4 Complete the following with respect to separation techniques.
(a) Principle - Difference in size of components in the solid - solid mixture , Method - _________________________________ , Example ___________________________________________
(b) Principle , ______________________________________ , Method - Evaporation , Example - ____________________________________
(c) Principle - ______________________________________ , Method - _____________________________________ Example - Mixture of sand and iron filings.
(d) Principle - One component of solid - solid mixture sublimes , Method - __________________________________________ , Example - ______________________________________________
(e) Principle - ____________________________________________ Method - Decantation , Example - ___________________________________________________
Multiple Choice Questions
Q-1 The method used to separate tea leaves from tea :

(i)

Evaporation

(ii)

Filtration

(iii)

Straining

(iv)

Sieving
Q-2 The method used to separate pebbles from sand:

(i)

Hand picking

(ii)

Sedimentation

(iii)

Decantation

(iv)

Washing
Q-3 The process of transferring the supernatent liquid without disturbing the sediment is called:

(i)

Sedimentation

(ii)

Decantation

(iii)

Filtration

(iv)

Sublimation
Q-4 A porous medium which allows only the liquid to pass through it is called:

(i)

Sieve

(ii)

Strainer

(iii)

Filter paper

(iv)

All of these
Q-5 The method used to separate salt from sea water:

(i)

Filtration

(ii)

Evaporation

(iii)

Sublimation

(iv)

Sedimentation
Q-6 Which of the following statements refer to the importance of pure substances?

(i)

Impurities in medicines could be harmful to health

(ii)

Impurities in drinking water could cause diseases like typhoid and cholera

(iii)

In research work, pure substances give accurate results

(iv)

All of the above
Q-7 Magnetic separation can be carried out if one of the components of the mixture is:

(i)

Sulphur

(ii)

Iron

(iii)

Salt

(iv)

Ammonium chloride
Q-8 For which mixture can sublimation be used to separate the components?

(i)

Iodine + Ammonium chloride

(ii)

Powdered camphor + Iodine

(iii)

Sodium chloride + Ammonium chloride

(iv)

All of these
Q-9 Which of the following will sublime at room temperature?

(i)

Camphor

(ii)

Naphthalene

(iii)

Iodine

(iv)

None of these
Q-10 Filtration is used to separate a mixture of water and:

(i)

Fine insoluble solid

(ii)

Fine soluble solid

(iii)

Coarse insoluble solid

(iv)

None of these
Chapter-5   Water
Q-1 Answer the following questions.
(a) Name the three states of water.
(b) Why is water called a universal solvent?
(c) State the difference between unsaturated solution and a saturated solution.
(d) State three characteristics of drinking water.
(e) State five uses of water.
Q-2 Give the following physical constants of water:
(a) Boiling point
(b) Freezing point
(c) Density
Q-3 State one characteristic of the following:
(a) Natural water
(b) Rainwater
(c) River water
(d) Lake water
(e) Sea water
(f) Groundwater
(g) Unsaturated solution
(h) Saturated solution
(i) Supersaturated solution
Q-4 Explain briefly:
(a) Underground water is usually pure.
(b) Seawater has a salty taste.
(c) Certain spring water is called mineral water.
(d) Groundwater raised by hand pumps is preferred to raising water from wells.
Q-5 Name
(a) The purest form of natural water.
(b) The most impure form of natural water.
(c) A waterborne disease
Q-6 Select the appropriate letters from the list provided below and label the given diagram.
(a) Evaporation from land and transpiration from plants.
(b) Surface run-off
(c) Precipitation
(d) Evaporation from ocean
(e) Clouds
(f) Groundwater
(g) Water table
(h) Invisible water vapour
(i) Groundwater flowing to ocean
(j) Vapour cools forming clouds causing precipitation.
Multiple Choice Questions
Q-1 Water exists in the following state:

(i)

Solid

(ii)

Liquid

(iii)

Gas

(iv)

All of these
Q-2 About ____________ % of our body weight is water.

(i)

65-75

(ii)

25-35

(iii)

85-95

(iv)

15-25
Q-3 Which of the following is NOT surface water?

(i)

Spring

(ii)

Pond

(iii)

River

(iv)

Ocean
Q-4 This is the purest form of natural water:

(i)

River water

(ii)

Rainwater

(iii)

Seawater

(iv)

Well water
Q-5 The salty taste of seawater is due to dissolved:

(i)

Common salt

(ii)

Oxygen

(iii)

Iron sulphide

(iv)

Carbon dioxide
Q-6 This is an underground water resource:

(i)

Stream

(ii)

Spring

(iii)

Pond

(iv)

None of these
Q-7 Water which is fit for drinking is called:

(i)

Portable water

(ii)

Potable water

(iii)

Filtered water

(iv)

Mineral water
Q-8 Oceans cover about ________________ % of the Earth's surface.

(i)

30

(ii)

15

(iii)

50

(iv)

70
Q-9 Which of the following is a device to raise underground water?

(i)

Hand pump

(ii)

Pulley system

(iii)

Elevator

(iv)

Both (a) and (b)
Q-10 Mineral water is sourced from:

(i)

Rivers

(ii)

Lakes

(iii)

Streams

(iv)

Springs
Q-11 Which of the following is a stage in the purification of natural water for drinking?

(i)

Coagulation

(ii)

Filtration

(iii)

Chlorination

(iv)

All of these
Q-12 Which is a water borne disease?

(i)

Typhoid

(ii)

Cholera

(iii)

Dysentery

(iv)

All of these
Q-13 Which of the following is a characteristic of drinking water?

(i)

It is colourless and odourless

(ii)

Contains mineral salts

(iii)

Contains dissolved 0 2 and CO2

(iv)

All of these
Q-14 Which statement is NOT true for water?

(i)

Pure water boils at 100°C and freezes at 0°C

(ii)

Pure water is a good conductor of electricity

(iii)

The density of pure water is 1 g/cm3

(iv)

Water is a universal solvent
Q-15 Seawater is unfit for drinking because it contains:

(i)

Excess salts

(ii)

Excess CO2

(iii)

Excess bacteria

(iv)

None of these
Chapter-6   Air and Atmosphere
Q-1 Answer the following questions.
(a) Differentiate between air and atmosphere.
(b) Why do plants need nitrogen?
(c) How is the nitrogen present in plant and animal bodies returned to the atmosphere?
Q-2 Match the items in column A with items in column B. (More than one matching is possible.)
Q-3 Name a gas that fits the following description
(a) Colourless, odourless, lighter than air, non-combustible, non-supporter of combustion.
(b) Colourless, odourless, heavier than air, non-combustible, non-supporter of combustion.
(c) Colourless, odourless, heavier than air, non-combustible, supporter of combustion.
Q-4 State whether the following statements are true or false:
(a) Carbon dioxide is required by plants for making proteins.
(b) Nitrogen of the air is an important constituent of proteins.
(c) Removal of water from plant bodies in the form of water vapour is called transpiration.
(d) The process of photosynthesis releases carbon dioxide into the air.
(e) Burning of fuel releases oxygen into the air.
Q-5 Draw neatly labelled sketches to show the following:
(a) The Oxygen-Carbon dioxide cycle
(b) The Nitrogen Cycle
Q-6 Answer the following questions.
(a) Differentiate between air and atmosphere.
(b) Why do plants need nitrogen?
(c) How is the nitrogen present in plant and animal bodies returned to the atmosphere?
Q-7 Match the items in column A with items in column B. (More than one matching is possible.)
Q-8 Name a gas that fits the following description
(a) Colourless, odourless, lighter than air, non-combustible, non-supporter of combustion.
(b) Colourless, odourless, heavier than air, non-combustible, non-supporter of combustion.
(c) Colourless, odourless, heavier than air, non-combustible, supporter of combustion.
Q-9 State whether the following statements are true or false:
(a) Carbon dioxide is required by plants for making proteins.
(b) Nitrogen of the air is an important constituent of proteins.
(c) Removal of water from plant bodies in the form of water vapour is called transpiration.
(d) The process of photosynthesis releases carbon dioxide into the air.
(e) Burning of fuel releases oxygen into the air.
Q-10 Draw neatly labelled sketches to show the following:
(a) The Oxygen-Carbon dioxide cycle
(b) The Nitrogen Cycle
Multiple Choice Questions
Q-1 Which of these gases is not present in the Earth's atmosphere?

(i)

Hydrogen

(ii)

Ozone

(iii)

Argon

(iv)

Nitrogen
Q-2 The ozone layer protects us from:

(i)

Infrared rays

(ii)

Ultraviolet rays

(iii)

Visible rays

(iv)

None of these
Q-3 Nature maintains the proportion of gases in the air through:

(i)

Nitrogen cycle

(ii)

Carbon cycle

(iii)

water cycle

(iv)

All of these
Q-4 Which of the following statement is true about air?

(i)

Air is a mixture of gases

(ii)

Air exerts pressure

(iii)

Air has mass and it occupies space

(iv)

All of these
Q-5 The percentage of nitrogen in the air is about:

(i)

80%

(ii)

20%

(iii)

60%

(iv)

None of these
Q-6 Nitrogen is used by plant to make:

(i)

Carbohydrates

(ii)

Proteins

(iii)

Fats

(iv)

Only (a) and (b)
Q-7 Which is a test to identify carbon dioxide gas?

(i)

It relights a glowing splinter

(ii)

It extinguishes a glowing splinter

(iii)

It turns lime water milky

(iv)

Both (b) and (c)
Q-8 Which statement is true for oxygen?

(i)

It is 1.5 times heavier than air

(ii)

It is 1.5 times lighter than air

(iii)

It allows substances to burn in it

(iv)

It is highly soluble in water
Q-9 Humidity is the amount of _______________ present in the air.

(i)

Nitrogen

(ii)

Oxygen

(iii)

Water vapour

(iv)

Inert gases
Q-10 Burning of fossil fuels releases ______________ into the atmosphere.

(i)

Nitrogen dioxide

(ii)

Sulphur dioxide

(iii)

Carbon dioxide

(iv)

Nitrogen
Q-11 Which statement refers to the dangers of global warming?

(i)

Cause glaciers and snow to melt

(ii)

Cause floods and climate change

(iii)

Cause animals to lose their homes

(iv)

All of these
Q-12 During photosynthesis, plant take in the following gas:

(i)

Carbon dioxide

(ii)

Oxygen

(iii)

Nitrogen

(iv)

Both (a) and (c)
Q-13 By the process of photosynthesis, green plants prepare food in the form of:

(i)

Carbohydrates

(ii)

Proteins

(iii)

Fats

(iv)

All of these
Q-14 Which is a greenhouse gas?

(i)

Carbon dioxide

(ii)

Methane

(iii)

Nitrous oxide

(iv)

All of these
Q-15 During photosynthesis, plant give out the following gas:

(i)

Carbon dioxide

(ii)

Oxygen

(iii)

Nitrogen

(iv)

Both (a) and (c)