Chemistry Environmental Chemistry MCQs Chapter 16 Class 12 - PLS Academy

Chemistry Environmental Chemistry MCQs – Chapter 16 Class 12

Chemistry Environmental Chemistry is an important chapter of Class 12 Chemistry and plays a significant role in FSc Part-II exams and entry test preparation. MCQs from this chapter are frequently included in MDCAT, NUMS, AKU, NUST, UET ECAT, and board examinations. This chapter covers key topics such as air, water, and soil pollution, greenhouse effect, ozone depletion, acid rain, and methods of pollution control and environmental protection.

PLS Academy

Get Access to 20 thousands+ MCQs Including Topical MCQs, Practice Tests, Mock Tests, Solved Past Papers, Flashcards, Notes, FLPS, and Much More.

UNLOCK PREMIUM🔐

443

Chemistry Ch 16 Class 12 ENVIRONMENTAL CHEMISTRY

This is the Free Access to Limited MCQs. Enroll to PLS Boost Premium Bundle to Get More MCQs HERE

1 / 63

Measuring ‘Biochemical Oxygen Demand’ (ROD) is a method used for:

Estimating the amount of organic matter in sewage water for determining quality

Measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale.

Working out the efficiency of RBCs, about their capacity to carry oxygen.

Working out the efficiency of oil driven automobile engines.

2 / 63

Which of the following is a water cleaning halogen?

3 / 63

Which one substance is used to remove both H2S and carbon dioxide from biogas?

Sodium oxide

Calcium oxide

Both a and b

None of the above

4 / 63

Which of the following is a secondary pollutant?

CO2

Sulphur Oxide

Nitrogen Oxide

5 / 63

Ozone Is

6 / 63

Earth’s crust Is Included In which sphere?

Lithosphere

Hydrosphere

Atmosphere

Aerosphere

7 / 63

Which one is correct about Incineration of Industrial waste?

Ash buried in sea water.

Secondary chamber is maintained at temperature range 650 C to 1100 C

Smoke stacks emit oxides of nitrogen and carbo

Solids wastes are the significant sources of dioxins

8 / 63

Which of the following gases has least concentration in air a

CO2

9 / 63

Ozone absorbs

Radioactive radiations

All of these

10 / 63

Which one of these Is toxic?

Nitrous oxide

Nitric oxide

Sulphur dioxide

Carbon dioxide

11 / 63

Treatment of water which is very effective in killing of pathogens is:

Aeration

Coagulation

Landfill

Chlorine usage

12 / 63

NO2 in atmosphere absorbs moisture to form?

HNO3

HNO2

Both a and b

13 / 63

Function of ozone Is?

To filter UV radiations

Act as a reducing agent

Act as an antibiotic

None of these

14 / 63

Global scale SO2 is produced by

Combustion

Fossil fuels

Volcano

None of these

15 / 63

What is the major reason for S02 emissions?

Agriculture

Volcanic eruptions

Fuel combustion

All of the above

16 / 63

Which of the following causes suffocation?

S02

CO2

Fog

All of these

17 / 63

The best yield of 502 can be obtained by which of the following:

Burning of coal

Excess of oxygen

Fertilization

Oxides of pyrites

18 / 63

Chloro-fluoro carbons cause

Radiations pollution

Water pollution

Air pollution

Soil pollution

19 / 63

In the atmosphere, CO2 is about:

FMDC 2018
Chemistry
Environmental Chemistry
Elimination Tool:

A) 0.01％

B) 0.03％

C) 0.05％

D) 0.09％

20 / 63

If CO2 level increase from the normal level, what will happen?

ETEA 2017
Chemistry
Environmental Chemistry
Elimination Tool:

A) Decrease in sea level

B) Increase in sea level

C) Longer winter season

D) Daytime will increase

21 / 63

Which of the following pollutant decolorize the skin?

ETEA 2019
Chemistry
Environmental Chemistry
Elimination Tool:

A) Mercury

B) Arsenic

C) Lead

D) Cadmium

22 / 63

Photochemical smog is primarily caused by

ETEA 2019
Chemistry
Environmental Chemistry
Elimination Tool:

A) O3

B) NO2

C) SO3

D) CO2

23 / 63

Which of the following is the most environmentally-friendly source to derive energy?

UHS 2017 Reconduct
Chemistry
Environmental Chemistry
Elimination Tool:

A) Lead-acid accumulator

B) H2- O2 fuel cell

C) Silver Oxide Battery

D) Alkaline battery

24 / 63

The substance for the separation of isotopes is firstly converted into the

UHS 2016
Chemistry
Environmental Chemistry
Elimination Tool:

A) Neutral state

B) Free state

C) Vapour state

D) Charged state

25 / 63

The gas which is mainly produced in landfills from the waste is:

UHS 2016
Chemistry
Environmental Chemistry
Elimination Tool:

A) CH4

B) CO2

C) SO2

D) Cl2

26 / 63

Ozone concentration is measured in:

UHS 2016
Chemistry
Environmental Chemistry
Elimination Tool:

A) Debye units

B) Dupont units

C) Debacle units

D) Dobson units

27 / 63

The yellowish-brown color in photochemical smog is due to the presence of:

UHS 2013
Chemistry
Environmental Chemistry
Elimination Tool:

A) Sulphur dioxide

B) Carbon monoxide

C) Carbon dioxide

D) Nitrogen dioxide

28 / 63

Aerobic decomposition of organic matter i.e. glucose by bacteria in water sediments produces

UHS 2013
Chemistry
Environmental Chemistry
Elimination Tool:

A) Propene

B) Ethane

C) Methane

D) Butane

29 / 63

Unpolluted rain water has a pH of:

UHS 2013
Chemistry
Environmental Chemistry
Elimination Tool:

A) 4.9

B) 5.6

C) 5.3

D) 7.0

30 / 63

Which one of the following pollutants can cause death of a person by binding with
haemoglobin of red blood cells?

UHS 2014
Chemistry
Environmental Chemistry
Elimination Tool:

A) Chlorofluorocarbons

B) Oxides of Sulphur

C) Carbon monoxide

D) Oxides of nitrogen

31 / 63

Polystyrene is an additional polymer. Which one of the following structures represents
the monomer of polystyrene?

UHS 2014
Chemistry
Environmental Chemistry
Elimination Tool:

A) CH2=CH2

B) CH2=CH-CH3

C) CH2=CH-Cl

D) CH2=CH-C6H5

32 / 63

___________ is an eye irritant.

UHS 2014
Chemistry
Environmental Chemistry
Elimination Tool:

A) Peroxyacetyl nitrate

B) Peroxyacetyl nitrite

C) Peroxy Methoxy aniline

D) Peroxyacetyl aniline

33 / 63

The pH of acid rain is

UHS 2014
Chemistry
Environmental Chemistry
Elimination Tool:

A) 7

B) Between 5 and 7

C) Below 5

D) Between 7 and 14

34 / 63

Peroxyacetyl nitrate is an irritant to human beings and it effects:

UHS 2011
Chemistry
Environmental Chemistry
Elimination Tool:

A) Nose

B) Stomach

C) Ears

D) Eyes

35 / 63

The suspected liver carcinogen which also has negative reproduction and developmental effect on humans is:

UHS 2011
Chemistry
Environmental Chemistry
Elimination Tool:

A) Iodoform

B) Bromoform

C) Tropoform

D) Chloroform

36 / 63

The unpolluted natural rainwater is slightly acidic due to the reaction of rain water with:

UHS 2011
Chemistry
Environmental Chemistry
Elimination Tool:

A) Sulphur dioxide

B) Oxides of nitrogen

C) Carbon dioxide

D) Hydrogen present in air

37 / 63

The acid rain water has pH:

UHS 2012
Chemistry
Environmental Chemistry
Elimination Tool:

A) Below 5

B) 7

C) Between 5 and 7

D) Between 7 and 14

38 / 63

Which is the metal, whose elevated concentration is harmful to fish as it clogs the gills thus causing suffocation?

UHS 2012
Chemistry
Environmental Chemistry
Elimination Tool:

A) Na

B) Pb

C) Zn

D) Al

39 / 63

The increase in the concentration of oxidizing agents in smog like H2O2, HNO3, PAN, and ozone in the air is called:

UHS 2012
Chemistry
Environmental Chemistry
Elimination Tool:

A) Carbonated smog

B) Nitrated smog

C) Photochemical smog

D) Sulphonated smog

40 / 63

The biggest source of acid rain is the oxide of

UHS 2015
Chemistry
Environmental Chemistry
Elimination Tool:

A) N

B) S

C) O

D) C

41 / 63

Urea is the most widely used nitrogen fertilizer in Pakistan. Its composition is:

UHS 2015
Chemistry
Environmental Chemistry
Elimination Tool:

A) NH2CO

B) N2H5CO2

C) N2H4CO2

D) N2H4CO

42 / 63

About 80% of ammonia is used for the production of

UHS 2015
Chemistry
Environmental Chemistry
Elimination Tool:

A) Explosives

B) Fertilizers

C) Nylon

D) Polymers

43 / 63

[Ti(H2O)6]3+ transmits

UHS 2015
Chemistry
Environmental Chemistry
Elimination Tool:

A) Yellow and Red light

B) Yellow and Blue light

C) Red and white light

D) Red and blue light

44 / 63

Bacteria plays an important role in:

PMC 2021 Tested
Chemistry
Environmental Chemistry
Elimination Tool:

A) Phosphorus Cycle

B) Nitrogen Cycle

C) Carbon Cycle

D) All of these

45 / 63

Which of the following would react with ozone in the atmosphere?

UHS 2018
Chemistry
Environmental Chemistry
Elimination Tool:

A) F*

B) O2

C) O*

D) Cl*

46 / 63

Percentage of nitrogen by volume in air is:

UHS 2018
Chemistry
Environmental Chemistry
Elimination Tool:

A) 78%

B) 50%

C) 20%

D) 98%

47 / 63

Which of the following gas, when ignited, burns with a blue flame and is not very soluble in water?

UHS 2018
Chemistry
s and p Block Elements
Environmental Chemistry
Elimination Tool:

A) O2

B) CO2

C) N2

D) He

48 / 63

The essential property of a fertilizer is that is should be:

UHS 2018
Chemistry
Environmental Chemistry
Elimination Tool:

A) Immiscible

B) Highly soluble

C) Insoluble

D) Partially soluble

49 / 63

Which of these pollutants is produced by burning of coal and causes acid rain.

UHS 2018
Chemistry
Environmental Chemistry
Elimination Tool:

A) NO

B) CO2

C) SO2

D) CO

50 / 63

Which of the following compounds is responsible for the depletion of ozone layer?

UHS 2019
Chemistry
Environmental Chemistry
Elimination Tool:

A) Chlorofluorocarbons

B) Carbon tetrachlorie

C) Methane

D) Hydroflorocarbons

51 / 63

CFCs are organic compounds, that are derivatives of saturated hydrocarbons. They have high bond dissociation values therefore they are inert and non-toxic for living organisms.

The word CFCs stands for:

UHS 2019
Chemistry
Environmental Chemistry
Elimination Tool:

A) Chlorofluorocarbons

B) Carbonfluorochlorines

C) Clorofluorocarbonos

D) Chlorofluoridecarbons

52 / 63

Free Nitrogen and Oxygen are present in atmosphere but they do not react with each other under normal conditions because:

UHS 2019
Chemistry
Environmental Chemistry
Elimination Tool:

A) Nitrogen requires a catalyst

B) Oxygen is very inactive

C) Oxygen is found in less concentration

D) Nitrogen is highly inactive gas

53 / 63

Chlorofluorocarbons (CFCs) are important compounds that are used as refrigerants but these are also responsible for Ozone layer depletion. If a Chlorofluorocarbon CFCl3 is present in stratosphere, which of it’s reaction intermediates are actually responsible for the breakdown of the ozone molecule?

UHS 2019
Chemistry
Environmental Chemistry
Elimination Tool:

A) CFCl2* and Cl*

B) Cl* and ClO*

C) CFCl2* and ClO*

D) CFCl2 and CFCl3

54 / 63

The unit ___ is commonly used by meteorologists

PMC Sample 3
Chemistry
Environmental Chemistry
Elimination Tool:

A) Bar

B) centibar

C) millibar

D) kilobar

55 / 63

Which of the following is the most environmentally friendly source to derive energy?

NUMS 2017
Chemistry
Environmental Chemistry
Elimination Tool:

A) Lead-acid accumulator

B) H2- O2fuel cell

C) Silver oxide battery

D) Alkaline battery

56 / 63

In the atmosphere, CO2is about?

NUMS 2018
Chemistry
Environmental Chemistry
Elimination Tool:

A) 0.01 %

B) 0.03 %

C) 0.05 %

D) 0.09 %

57 / 63

Which of the following is not a primary pollutant of the troposphere?

NUMS 2019 Cancelled
Chemistry
Environmental Chemistry
Elimination Tool:

A) Carbon dioxide

B) Sulfur dioxide

C) Carbon monoxide

D) Ammonia

58 / 63

What is formed by a series of complex reactions of ozone with water in the troposphere that are driven by sunlight?

NUMS 2019 Cancelled
Chemistry
Environmental Chemistry
Elimination Tool:

A) O radical

B) H radical

C) OH radical

D) H3O radical

59 / 63

The increasing number of CFC production for industrial use has been a major contributor to the depletion of ozone molecules in the stratosphere. When CFCs diffuses slowly to the atmosphere in the presence of UV light between 175 nm to 220 nm, the ozone layer decomposes. If 1 mole of CFCl3 (Freon – 110) has been released into the air, how many moles of oxygen is produced from the photodecomposition of ozone?

NUMS 2019 Cancelled
Chemistry
Environmental Chemistry
Elimination Tool:

A) 1

B) 2

C) 3

D) 4

60 / 63

Which of the pair of gases is not a greenhouse gas?

NUMS 2019 Cancelled
Chemistry
Environmental Chemistry
Elimination Tool:

A) Carbon dioxide and methane

B) Carbon dioxide and nitric oxide

C) Nitrogen and oxygen

D) Water vapour and ozone

61 / 63

Which of the following is secondary pollutant?

NUMS 2019 Reconduct
Chemistry
Environmental Chemistry
Elimination Tool:

A) CO

B) SO2

C) PAN

D) NO2

62 / 63

Which one of the following is NOT an advantage of synthetic fiber?

NTS 2016 SMBBMC
Chemistry
Environmental Chemistry
Elimination Tool:

B) Ease of ironing

C) Softness

D) Heat retention

E) Absorbs the sweat

63 / 63

The formula of “rock salt” is:

NTS 2012
Chemistry
Environmental Chemistry
Elimination Tool:

A) NaOH

B) NaHCO3

C) Na2CO3

E) NaCl

Your score is

The average score is 57%

Importance of Environmental Chemistry MCQs

A strong understanding of Environmental Chemistry helps students explain causes and effects of pollution, environmental problems, and preventive measures. Exams often include MCQs on types of pollutants, environmental laws, and methods to control pollution. Practicing chapter-wise MCQs improves conceptual clarity, accuracy, and confidence for competitive exams.

Effective Strategy for Free Preparation

For effective preparation, students should revise environmental concepts, causes and effects of pollution, and preventive strategies regularly, and solve topic-wise MCQs consistently. Attempting free tests and past paper questions helps identify important concepts and repeated exam patterns. PLS Academy provides structured MCQs and free resources to support Chemistry Environmental Chemistry preparation and other Class 12 Chemistry chapters.

JazakAllah