chemistry MCQs - 9th class Chapter 10 Mcqs

1

What percentage of clean, dry air is composed of nitrogen?

A

21%

B

78%

C

1%

D

0.03%

2

Which gas is a major component of the remainder of air after nitrogen and oxygen?

A

Carbon dioxide

B

Methane

C

Noble gases

D

Sulphur dioxide

3

What is the primary source of carbon monoxide (CO) as an air pollutant?

A

Decomposition of vegetation

B

Car engines

C

Combustion of fossil fuels with sulfur

D

Incomplete combustion of carbon-containing fuels

4

Methane (CH4) is primarily released from which source?

A

Volcanic eruptions

B

Industrial processes

C

Decomposition of vegetation and digestion in animals

D

Combustion of low-sulfur fuels

5

Oxides of nitrogen (NOx), which contribute to acid rain and smog, are mainly produced by what?

A

Car engines

B

Planting trees

C

Flue gas desulfurization

D

Digestion in animals

6

Sulphur dioxide (SO2) is a major air pollutant originating from:

A

The use of catalytic converters

B

The decomposition of waste

C

The combustion of fossil fuels containing sulfur compounds

D

Photosynthesis

7

What environmental problem is directly associated with higher levels of carbon dioxide and methane?

A

Ozone layer depletion

B

Water pollution

C

Global warming

D

Soil erosion

8

According to the text, what is a primary adverse effect of carbon monoxide?

A

It causes acid rain

B

It is a toxic gas

C

It increases respiratory problems

D

It contributes to global warming

9

Particulates in the air are associated with which health risk?

A

Acid rain

B

Global warming

C

Increased risk of respiratory problems and cancer

D

Suffocation

10

What are the main environmental impacts of oxides of nitrogen (NOx)?

A

Only respiratory problems

B

Only photochemical smog

C

Acid rain, photochemical smog, and respiratory problems

D

Only climate change

11

How do greenhouse gases like carbon dioxide cause global warming?

A

By depleting the ozone layer

B

By increasing the acidity of rain

C

By reducing thermal energy loss to space

D

By directly heating the Earth's core

12

What is the role of a catalytic converter in a vehicle?

A

To increase fuel efficiency

B

To cool the engine

C

To reduce harmful emissions like CO and NOx

D

To increase the engine's power

13

Photosynthesis is the reaction between which two substances?

A

Oxygen and water

B

Nitrogen and water

C

Carbon dioxide and water

D

Carbon monoxide and oxygen

14

The branch of chemistry that deals with pollutants in the environment is called:

A

Organic Chemistry

B

Biochemistry

C

Analytical Chemistry

D

Environmental Chemistry

15

The concentration of a pollutant is commonly expressed in which unit?

A

Kilograms per liter (kg/L)

B

Parts per million (ppm)

C

Molecules per cubic meter

D

Grams per mole (g/mol)

16

Which of the following is NOT listed as a major air pollutant?

A

Ozone (O3)

B

Smog

C

Hydrocarbons

D

Water vapour (as a pollutant)

17

Smog, which is prevalent in many Pakistani cities in winter, is described as a mixture of:

A

Smoke and fog

B

Dust and wind

C

Rain and pollutants

D

Ozone and oxygen

18

What is the pH value below which rain is considered acid rain?

A

7.0

B

6.5

C

5.6

D

8.0

19

Who is known as the 'Father of Acid Rain' for showing the link between acid rain and pollution?

A

Robert Angus Smith

B

John Dalton

C

Antoine Lavoisier

D

Dmitri Mendeleev

20

Acid rain can dissolve and wash away toxic substances from the soil, such as:

A

Nitrogen and oxygen

B

Calcium and magnesium

C

Aluminium and mercury

D

Sodium and potassium

21

The progressive warming up of the Earth's surface due to the blanketing effect of certain gases is called:

A

The Ozone Effect

B

The Atmospheric Effect

C

The Greenhouse Effect

D

The Solar Effect

22

Greenhouse gases prevent thermal energy from escaping into space by absorbing what type of radiation?

A

Shortwave radiation

B

Longwave radiation

C

UV radiation

D

X-ray radiation

23

Besides carbon dioxide, which other gas is mentioned as a major greenhouse gas?

A

Oxygen

B

Nitrogen

C

Methane

D

Sulphur dioxide

24

What is a major consequence of rising sea levels caused by global warming?

A

Increased agricultural productivity

B

Threat to low-lying coastal areas

C

Shorter winters

D

Reduced rainfall

25

The process where plants clean the air by absorbing carbon dioxide is called:

A

Respiration

B

Transpiration

C

Photosynthesis

D

Decomposition

26

What is the function of a three-way catalytic converter regarding nitrogen oxides (NOx)?

A

It oxidizes NOx to N2 and O2

B

It reduces NOx into elemental nitrogen and oxygen

C

It converts NOx into hydrocarbons

D

It combines NOx with CO

27

What substance is used in flue gas desulfurization to remove sulfur dioxide?

A

Calcium oxide

B

Sodium chloride

C

Hydrochloric acid

D

Carbon monoxide

28

An Air Quality Index (AQI) value under what number is considered good?

A

100

B

75

C

50

D

150

29

An AQI over 300 is considered to be:

A

Good

B

Moderate

C

Unhealthy

D

Hazardous

30

Which type of mask is mentioned as having better filtration capabilities against fine particles?

A

Cloth mask

B

Dust mask

C

Surgical mask

D

N95 mask

31

The complete combustion of carbon-containing fuels primarily produces:

A

Carbon monoxide

B

Soot

C

Carbon dioxide

D

Methane

32

What happens to the amount of oxygen in the atmosphere due to photosynthesis?

A

It decreases

B

It remains unchanged

C

It increases

D

It converts to ozone

33

What historical monument in India is mentioned as deteriorating due to acid rain?

A

The Red Fort

B

The Qutub Minar

C

The Taj Mahal

D

The Gateway of India

34

What happens to lakes and streams that are affected by particulate matter?

A

They become warmer

B

They may become acidic

C

They evaporate faster

D

Their water level rises

35

Which of the following is considered a renewable energy resource?

A

Natural gas

B

Coal

C

Petroleum

D

Wind

36

In the reaction 2NO + 2CO -> 2CO2 + N2, what is being reduced?

A

CO

B

CO2

C

NO

D

N2

37

What is the main reason for the increase of methane in the atmosphere?

A

Burning of fossil fuels

B

Volcanic activity

C

Increased decay of vegetation and farming

D

Industrial smoke

38

Which of the following is a direct effect of smog on human health?

A

Causes acid rain

B

Leads to global warming

C

Can cause allergies, asthma, and lung infections

D

Increases blood oxygen levels

39

How does acid rain affect soil nutrients?

A

It adds nutrients to the soil

B

It has no effect on nutrients

C

It dissolves and washes away nutrients

D

It converts nutrients into toxic substances

40

What is the estimated percentage of oxygen in the atmosphere?

A

78%

B

1%

C

21%

D

0.03%

41

What is the collective term for oxides of nitrogen like NO and NO2?

A

NOx

B

SOx

C

COx

D

HNx

42

The chemical formula for glucose, produced during photosynthesis, is:

A

C6H12O6

B

CO2

C

H2O

D

CH4

43

What tool can be installed to detect increased levels of carbon monoxide from faulty appliances?

A

AQI meter

B

Smoke detector

C

Carbon monoxide detector

D

Air cleaner

44

Which pollutant stops red blood cells from carrying oxygen?

A

Carbon dioxide

B

Carbon monoxide

C

Sulphur dioxide

D

Ozone

45

How is ground-level ozone formed?

A

By the complete combustion of fuels

B

Reaction between NOx and VOCs in presence of light

C

From the decomposition of vegetation

D

By volcanic eruptions

46

What strategy is mentioned to reduce acid rain from vehicles?

A

Using low-sulfur fuels

B

Planting more trees

C

Using catalytic converters

D

Increasing engine temperature

47

What effect does global warming have on seasons in moderate regions?

A

Winters become longer and colder

B

Summers become shorter and cooler

C

Winters become shorter and warmer

D

No change in seasons

48

Which human activity is identified as the main factor for environmental pollution?

A

Agriculture

B

Industrialization and Transportation

C

Population growth

D

All of the above

49

What happens to toxic substances like aluminum and mercury in soil due to acid rain?

A

They are neutralized

B

They evaporate

C

They are dissolved

D

They become solid