Environmental Chemistry MCQs

Prepare for the PPSC Analytical Chemist exam with this Environmental Chemistry Quiz, designed to test your knowledge of pollution, green chemistry, water treatment, and atmospheric chemistry. Strengthen your concepts with these expertly crafted MCQs and boost your exam success!

1. What is Environmental Chemistry?

A) Study of chemicals in space
B) Study of chemicals and pollutants resulting from human activities
C) Study of organic compounds in plants
D) Study of metals in the earth’s crust
Answer: B

2. Which of the following is NOT a component of the environment?

A) Atmosphere
B) Hydrosphere
C) Lithosphere
D) Magnetosphere
Answer: D

3. The thickness of the atmosphere is approximately:

A) 100 km
B) 500 km
C) 1000 km
D) 2000 km
Answer: C

4. Which gas is used by nitrogen-fixing bacteria?

A) O2
B) CO2
C) N2
D) He
Answer: C

5. Which layer of the atmosphere is closest to the Earth’s surface?

A) Stratosphere
B) Mesosphere
C) Thermosphere
D) Troposphere
Answer: D

6. Smog is a combination of:

A) Smoke and fog
B) Dust and rain
C) Gas and vapor
D) Snow and fog
Answer: A

7. Photochemical smog is also called:

A) Reducing smog
B) Oxidizing smog
C) Industrial smog
D) Acid smog
Answer: B

8. Which of the following is NOT a condition for photochemical smog formation?

A) Sunlight
B) Temperature below 10°C
C) Presence of NOx
D) Presence of VOCs
Answer: B

9. Acid rain is primarily caused by:

A) ( CO2 ) and ( O2 )
B) ( SO2 ) and ( NO2 )
C) ( N2 ) and ( He )
D) ( H2 ) and ( O3 )
Answer: B

10. The reaction between SO3 + H2O produces:

A) ( H2SO4 )
B) ( HNO3 )
C) ( H2CO3 )
D) ( HCl )
Answer: A

11. Which of the following is NOT an impact of acid rain?

A) Corrosion of metals
B) Increase in agricultural yield
C) Damage to aquatic life
D) Fading of fabric colors
Answer: B

12. The greenhouse effect is caused by:

A) ( O2 ) and ( N2 )
B) ( CO2 ) and water vapor
C) ( He ) and ( Ne )
D) ( SO2 ) and ( NO2 )
Answer: B

13. Global warming is linked to an increase in:

A) ( O2 ) levels
B) ( CO2 ) levels
C) ( N2 ) levels
D) ( H2 ) levels
Answer: B

14. Which of the following is a pollutant released by automobiles?

A) ( O2 )
B) ( N2 )
C) ( CO )
D) ( H2O )
Answer: C

15. Catalytic converters in vehicles use which catalyst?

A) Iron
B) Platinum
C) Copper
D) Zinc
Answer: B

16. The stratosphere is located at a height of:

A) 0-10 km
B) 20-40 km
C) 50-80 km
D) 100-150 km
Answer: B

17. Ozone in the stratosphere protects Earth by absorbing:

A) Visible light
B) Infrared radiation
C) UV radiation
D) X-rays
Answer: C

18. Which of the following destroys the ozone layer?

A) ( CO2 )
B) ( N2 )
C) CFCs
D) ( O2 )
Answer: C

19. The reaction Cl + O3 ….> ClO + O_2 ) represents:

A) Ozone formation
B) Ozone destruction
C) Photosynthesis
D) Combustion
Answer: B

20. Which of the following is a substitute for CFCs?

A) Freon
B) HCFCs
C) ( CO_2 )
D) ( SO_2 )
Answer: B

21. Water pollution is caused by:

A) Oxygen
B) Nitrogen
C) Pollutants
D) Sunlight
Answer: C

22. Which of the following is NOT a type of water pollution?

A) Thermal pollution
B) Suspended solids
C) Dissolved oxygen
D) Oil spillage
Answer: C

23. Oil spills primarily affect:

A) Air quality
B) Aquatic life
C) Soil fertility
D) Atmospheric pressure
Answer: B

24. Livestock waste can cause diseases like:

A) Diabetes
B) Dysentery
C) Asthma
D) Heart disease
Answer: B

25. Industrial waste often contains heavy metals such as:

A) ( Na ) and ( K )
B) ( Pb ) and ( Hg )
C) ( Ca ) and ( Mg )
D) ( Fe ) and ( Zn )
Answer: B

26. Chromium (VI) in leather industries is toxic and can cause:

A) Cancer
B) Anemia
C) Headaches
D) Skin rashes
Answer: A

27. Detergents in water bodies can bind to:

A) Oxygen
B) Heavy metals
C) Nitrogen
D) Carbon
Answer: B

28. Excessive use of chemical fertilizers leads to:

A) Decreased algae growth
B) Increased oxygen levels
C) Eutrophication
D) Reduced water temperature
Answer: C

29. Thermal pollution is caused by:

A) Release of heated water
B) Oil spills
C) Acid rain
D) Pesticides
Answer: A

30. Which parameter measures the oxygen required for organic decomposition in water?

A) COD
B) BOD
C) TDS
D) pH
Answer: B

31. The pH of pure water is:

A) 5
B) 7
C) 9
D) 11
Answer: B

32. Green Chemistry aims to:

A) Increase chemical hazards
B) Reduce hazardous substance use
C) Promote industrial waste
D) Ignore environmental issues
Answer: B

33. Which of the following is a principle of Green Chemistry?

A) Maximize waste
B) Use non-renewable resources
C) Design safer chemicals
D) Increase energy consumption
Answer: C

34. An example of a green insecticide is:

A) DDT
B) Toxaphene
C) Spinosad
D) Endrin
Answer: C

35. Which of the following is NOT a method to reduce laboratory risks?

A) Use safer solvents
B) Increase chemical derivatives
C) Prevent accidents
D) Design less hazardous syntheses
Answer: B

36. Atom economy in Green Chemistry refers to:

A) Wasting atoms
B) Maximizing atom usage in products
C) Using excess reagents
D) Ignoring reaction efficiency
Answer: B

37. Which of the following is a renewable feedstock?

A) Petroleum
B) Agricultural waste
C) Coal
D) Natural gas
Answer: B

38. The main goal of wastewater treatment is to:

A) Increase pollution
B) Remove contaminants
C) Add heavy metals
D) Reduce oxygen levels
Answer: B

39. Sedimentation techniques are used to remove:

A) Dissolved gases
B) Suspended solids
C) Radioactive waste
D) Thermal pollution
Answer: B

40. Which of the following is a toxic material in wastewater?

A) ( O2 )
B) ( N2 )
C) ( Hg )
D) ( CO2 )
Answer: C

41. The BOD level for very clean water is:

A) 1 mg/L
B) 5 mg/L
C) 10 mg/L
D) 20 mg/L
Answer: A

42. Which of the following is a source of nitrates in water?

A) Detergents
B) Fertilizers
C) Oil spills
D) Thermal pollution
Answer: B

43. The maximum permissible level of TDS in water is:

A) 100 mg/L
B) 400 mg/L
C) 1000 mg/L
D) 2000 mg/L
Answer: B

44. Which of the following metals is associated with mine drainage?

A) Sodium
B) Zinc
C) Potassium
D) Calcium
Answer: B

45. The primary source of phosphates in water is:

A) ( CO2 )
B) Detergents
C) ( O2 )
D) ( N2 )
Answer: B

46. Which of the following is NOT a water quality parameter?

A) BOD
B) COD
C) TDS
D) GDP
Answer: D

47. The protective layer of ozone is found in the:

A) Troposphere
B) Stratosphere
C) Mesosphere
D) Thermosphere
Answer: B

48. Which of the following is a greenhouse gas?

A) O2
B) N2
C) CO2
D) Ar
Answer: C

49. The industrial pollutant Cr(VI) is reduced to Cr(III) because:

A) Cr(III) is more toxic
B) Cr(III) is less toxic
C) Cr(VI) is harmless
D) Cr(III) is a gas
Answer: B

50. Which of the following is a consequence of thermal pollution?

A) Increased oxygen solubility
B) Decreased oxygen solubility
C) Reduced water temperature
D) Increased ice formation
Answer: B

51. The main purpose of a catalytic converter is to:

A) Increase CO emissions
B) Convert pollutants to less harmful forms
C) Reduce fuel efficiency
D) Increase NOx production
Answer: B

52. Which of the following is a volatile organic compound (VOC)?

A) CO2
B) Methane
C) O2
D) N2
Answer: B

53. The term “eutrophication” refers to:

A) Oxygen depletion due to excessive plant growth
B) Increase in water temperature
C) Reduction in water pH
D) Formation of acid rain
Answer: A

54. Which of the following is a natural source of HCl in the atmosphere?

A) Industrial emissions
B) Volcanic eruptions
C) Automobile exhaust
D) Forest fires
Answer: B

55. The primary component of photochemical smog is:

A) ( SO2 )
B) ( O3 )
C) ( CO2 )
D) ( N2 )
Answer: B

56. Which of the following is a method to control air pollution from vehicles?

A) Using leaded gasoline
B) Installing catalytic converters
C) Increasing fuel combustion
D) Reducing engine efficiency
Answer: B

57. The term “BOD” stands for:

A) Biological Oxygen Demand
B) Basic Oxygen Demand
C) Biodegradable Organic Debris
D) Biochemical Oxygen Depletion
Answer: A

58. Which of the following is a characteristic of green solvents?

A) High toxicity
B) Non-biodegradable
C) Low environmental impact
D) Derived from petroleum
Answer: C

59. The main objective of wastewater treatment is to:

A) Increase pollution levels
B) Remove contaminants for safe disposal/reuse
C) Add heavy metals to water
D) Reduce water volume
Answer: B

60. Which of the following is NOT a principle of Green Chemistry?

A) Waste minimization
B) Use of renewable feedstocks
C) Maximizing chemical derivatives
D) Designing safer chemicals
Answer: C