FBISE · Class 9

Class 9 Chemistry MCQs: Environmental Chemistry-Air

Practice chapter-wise MCQs with answers and explanations. Use the quiz mode for timed online tests.

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Quick revision

Class 9 Chemistry MCQs Environmental Chemistry-Air are one of the fastest ways to improve your board exam performance — especially when you practice with purpose, revise weak concepts, and learn from explanations.

On Prepzy, you can practice 101 MCQs from “Environmental Chemistry-Air” in Chemistry for FBISE. Each question is designed to mirror the style, wording, and concept-testing approach used in Pakistani board papers.

Use this chapter page to revise definitions, formulas, and key ideas, then attempt the MCQs in small sets. Track patterns in your mistakes: is it a concept gap, a calculation error, or a misread statement? Fixing the pattern is what raises your score.

If you’re preparing for matric / SSC Part exams, focus on understanding the concept first, then speed. MCQs reward clarity — not memorization. A clear concept turns into fast correct answers.

What to focus on

  • Primary focus: Environmental Chemistry-Air concepts tested in Class 9 Chemistry
  • Practice with instant answer-checking to reduce repeated mistakes
  • Revise common definitions, units, and standard results before timed practice
  • Aim for accuracy first, then build speed with short quizzes

Study tips

  • Read the question stem first, then scan options for distractors (near-correct choices).
  • If the chapter is formula-heavy, write a mini-formula sheet and revise it before every attempt.
  • After each practice set, re-attempt only the wrong MCQs to convert weak areas into strengths.
  • Mix easy + medium MCQs for momentum, then finish with hard questions for exam readiness.

MCQs (sample)

Showing 25 questions from this chapter. For a full timed test, use “Start online test”.

  1. 1. What has led to an increase in CO2 levels in the air?

    • Use of fossil fuels and deforestation
    • Increased solar radiation
    • Ocean currents
    • Volcanic eruptions
    Answer & explanation

    Correct: Use of fossil fuels and deforestation

    The content states that the increasing use of fossil fuels and deforestation have led to an increase in CO2 levels in the air.

  2. 2. What is one strategy to mitigate climate change?

    • Transition to renewable energy
    • Increase fossil fuel usage
    • Promote deforestation
    • Reduce recycling efforts
    Answer & explanation

    Correct: Transition to renewable energy

    Transitioning to renewable energy sources like wind and solar helps reduce greenhouse gas emissions.

  3. 3. What is the primary purpose of photosynthesis?

    • To produce glucose and oxygen
    • To decompose organic matter
    • To absorb carbon dioxide
    • To generate heat
    Answer & explanation

    Correct: To produce glucose and oxygen

    Photosynthesis uses solar energy to convert carbon dioxide and water into glucose and oxygen.

  4. 4. What is air pollution?

    • Air containing harmful particles and gases
    • Air that smells bad
    • Air that is cold
    • Air that has no color
    Answer & explanation

    Correct: Air containing harmful particles and gases

    Air pollution is defined as air that contains harmful particles and gases.

  5. 5. What is the approximate percentage of Nitrogen in dry air?

    • 78%
    • 21%
    • 0.93%
    • 0.038%
    Answer & explanation

    Correct: 78%

    The composition of dry air includes approximately 78% Nitrogen.

  6. 6. What is defined as any substance in the air, water or soil that has a harmful effect on the environment?

    • Pollutant
    • Acid rain
    • Dust
    • Emissions
    Answer & explanation

    Correct: Pollutant

    A pollutant is defined as any substance in the air, water, or soil that has a harmful effect on the environment.

  7. 7. What is the function of N95 masks?

    • They filter out particles and pollutants.
    • They provide oxygen supply.
    • They enhance breathing efficiency.
    • They absorb all gases completely.
    Answer & explanation

    Correct: They filter out particles and pollutants.

    N95 masks are designed specifically to filter out particles, including pollutants such as dust, smoke, and some airborne chemicals.

  8. 8. What can cause respiratory problems due to long-term exposure?

    • Pollutants in the air
    • Clean air
    • Moderate exercise
    • Healthy diet
    Answer & explanation

    Correct: Pollutants in the air

    Long-term exposure to pollutants like nitrogen oxides and particulate matter can damage the respiratory system.

  9. 9. What is the pH of normal rainwater?

    • 5.6
    • 2.1
    • 7.0
    • 4.0
    Answer & explanation

    Correct: 5.6

    Normal rainwater has a pH of 5.6 due to saturation with carbon dioxide.

  10. 10. What is the primary function of catalysts in catalytic converters?

    • To facilitate chemical reactions that convert harmful substances into less harmful ones.
    • To cool down the exhaust gases.
    • To increase fuel efficiency in engines.
    • To filter solid particles from the emissions.
    Answer & explanation

    Correct: To facilitate chemical reactions that convert harmful substances into less harmful ones.

    Catalysts in catalytic converters facilitate chemical reactions that convert harmful substances, such as nitrogen oxides, into less harmful substances.

  11. 11. Which of the following is NOT identified as a greenhouse gas?

    • Carbon dioxide
    • Water vapour
    • Methane
    • Oxygen
    Answer & explanation

    Correct: Oxygen

    The content lists carbon dioxide, water vapour, and methane as greenhouse gases, while oxygen is not mentioned as one.

  12. 12. Which renewable energy sources are mentioned in the strategies?

    • Wind, solar, hydro, geothermal
    • Coal and oil
    • Natural gas and nuclear
    • Biodiesel and ethanol
    Answer & explanation

    Correct: Wind, solar, hydro, geothermal

    The strategies include wind, solar, hydro, and geothermal as renewable energy sources.

  13. 13. Which of the following is a reactant in the photosynthesis equation?

    • Glucose
    • Oxygen
    • Carbon dioxide
    • Chlorophyll
    Answer & explanation

    Correct: Carbon dioxide

    Carbon dioxide is a reactant in the photosynthesis process represented by the equation.

  14. 14. Which of the following is a natural source of air pollution?

    • Forest fires
    • Cars
    • Factories
    • Power plants
    Answer & explanation

    Correct: Forest fires

    Forest fires are a natural process that releases smoke and dust particles into the air.

  15. 15. What percentage of dry air is Oxygen?

    • 21%
    • 78%
    • 0.93%
    • 0.0018%
    Answer & explanation

    Correct: 21%

    Dry air is approximately 21% Oxygen.

  16. 16. What produces significant amounts of sulphur dioxide when burned?

    • Fossil fuels
    • Natural gas
    • Solar power
    • Wind energy
    Answer & explanation

    Correct: Fossil fuels

    Sulphur is found naturally in fossil fuels, and burning them releases sulphur dioxide.

  17. 17. What type of filters do gas masks contain?

    • Activated carbon filters.
    • HEPA filters.
    • Paper filters.
    • Metal filters.
    Answer & explanation

    Correct: Activated carbon filters.

    Gas masks contain activated carbon filters that absorb certain gases and volatile organic compounds.

  18. 18. Which of the following is a significant risk factor for respiratory diseases?

    • Smoking
    • Regular exercise
    • Drinking water
    • Fresh fruits
    Answer & explanation

    Correct: Smoking

    Smoking damages the lungs and airways, making it a major risk factor for respiratory diseases.

  19. 19. What is the maximum recorded pH of acid rain mentioned in the content?

    • 5.6
    • 4.0
    • 2.1
    • 6.0
    Answer & explanation

    Correct: 2.1

    The pH of acid rain can be as low as 2.1 as stated in the content.

  20. 20. Which metals are commonly used as catalysts in catalytic converters?

    • Copper and zinc
    • Gold and silver
    • Platinum, palladium, and rhodium
    • Iron and nickel
    Answer & explanation

    Correct: Platinum, palladium, and rhodium

    Metals such as platinum, palladium, and rhodium are used as catalysts in catalytic converters.

  21. 21. What do greenhouse gases do with infrared radiation?

    • Absorb and re-radiate it
    • Reflect it back into space
    • Convert it into visible light
    • Destroy it entirely
    Answer & explanation

    Correct: Absorb and re-radiate it

    Greenhouse gases absorb the infrared radiation and re-radiate some of it, as stated in the content.

  22. 22. What does afforestation involve?

    • Planting trees
    • Cutting down trees
    • Building houses
    • Using more fossil fuels
    Answer & explanation

    Correct: Planting trees

    Afforestation refers to planting trees to increase carbon absorption through photosynthesis.

  23. 23. What role does chlorophyll play in photosynthesis?

    • It acts as a reactant
    • It absorbs sunlight
    • It produces oxygen
    • It converts glucose
    Answer & explanation

    Correct: It absorbs sunlight

    Chlorophyll absorbs sunlight, which is essential for the photosynthesis process.

  24. 24. What do termites release into the air?

    • Carbon dioxide
    • Hydrogen
    • Methane
    • Oxygen
    Answer & explanation

    Correct: Methane

    Termites release a large amount of methane into the air.

  25. 25. Which of the following gases has the smallest percentage in dry air?

    • Hydrogen
    • Krypton
    • Neon
    • Argon
    Answer & explanation

    Correct: Hydrogen

    Hydrogen has the smallest percentage (0.00005%) in dry air.

FAQs

Are these Class 9 Chemistry MCQs Environmental Chemistry-Air aligned with FBISE?

Yes. The MCQs are organized chapter-wise for FBISE and designed to match board exam patterns. If your teacher has added custom MCQs, they will also appear here.

How many MCQs should I practice from “Environmental Chemistry-Air” each day?

A good daily target is 20–40 MCQs with full review of mistakes. If you’re short on time, do 15 MCQs but read explanations carefully.

What’s the best way to revise this chapter before an exam?

Revise the chapter summary, list your weak sub-topics, then practice MCQs in timed sets. Re-attempt wrong questions after a short break to lock in learning.

Can I take an online test for this chapter?

Yes. Start a chapter quiz to simulate an online test. Use it to improve speed and accuracy under time pressure.

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