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Environmental Chemistry WBJEE MCQ & Practice Questions

Practice Environmental Chemistry MCQs for WBJEE Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

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Environmental Chemistry Revision Guide for WBJEE Chemistry

Environmental Chemistry is part of WBJEE Chemistry preparation. A strong revision plan should combine concept review with exam-style questions so that definitions, relationships, calculations and exceptions are recalled accurately.

Use the sample MCQs on this page to check understanding, then attempt the related ChemNexa tests for broader practice. When an answer is wrong, review the explanation and return to the underlying concept before attempting another set.

Important Topics

  • Core definitions and principles
  • Important equations or relationships
  • Common applications and examples
  • Frequently confused concepts
  • Exam-style multiple-choice questions
  • Error review and targeted revision

Revision Tip

Create a one-page summary of trends, structures, reactions, exceptions and key terminology for Environmental Chemistry, then test recall with mixed MCQs.

What to practise in Environmental Chemistry

Concept Revision

Revise definitions, principles, equations, trends and core ideas from Environmental Chemistry before attempting MCQs.

Exam-style MCQs

Use chapter-focused multiple-choice practice to improve accuracy, recall and application for WBJEE Chemistry.

Performance Practice

Attempt ChemNexa tests, review results and return to weak areas for another round of targeted revision.

Top 20 Environmental Chemistry MCQs with Answers

These public questions are selected from the exact Environmental Chemistry chapter, screened for topic relevance and deduplicated so repeated versions of the same MCQ are not shown publicly. Use them for quick revision, then sign in to attempt the complete test experience with more questions, results and performance review.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

1. The major anthropogenic greenhouse gas emitted by fossil-fuel combustion is:

  • A. N2
  • B. He
  • C. CO2
  • D. O2
Answer: C
Explanation: Combustion of carbon-based fuels releases carbon dioxide.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

2. The greenhouse effect warms Earth because certain gases absorb:

  • A. Radio waves only
  • B. Outgoing infrared radiation
  • C. All visible light
  • D. Cosmic rays only
Answer: B
Explanation: Greenhouse gases absorb and re-emit terrestrial infrared radiation.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

3. Methane is an important greenhouse gas with formula:

  • A. CH4
  • B. CH3OH
  • C. CO
  • D. C2H6
Answer: A
Explanation: Methane is CH4.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

4. Global warming refers broadly to:

  • A. Daily weather variation
  • B. Ozone formation only
  • C. Ocean tides
  • D. Long-term rise in average global surface temperature
Answer: D
Explanation: Global warming is the long-term increase in Earth's mean temperature.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

5. The stratospheric ozone layer primarily absorbs harmful:

  • A. Radio waves
  • B. Visible green light only
  • C. Ultraviolet radiation
  • D. Microwaves
Answer: C
Explanation: Ozone strongly absorbs biologically damaging UV radiation.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

6. Ozone depletion has been strongly associated with radicals generated from:

  • A. Water vapour only
  • B. CFCs
  • C. CO2 only
  • D. N2
Answer: B
Explanation: Photolysis of CFCs releases chlorine radicals that catalyse ozone destruction.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

7. A chlorine radical can destroy many ozone molecules because it acts:

  • A. Catalytically
  • B. As a stoichiometric precipitant
  • C. As a solvent
  • D. As a buffer
Answer: A
Explanation: Chlorine is regenerated in the ozone-destruction cycle.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

8. Photochemical smog is associated especially with:

  • A. Only NaCl aerosol
  • B. Only CO2 and water
  • C. Nitrogen gas alone
  • D. NOx and hydrocarbons under sunlight
Answer: D
Explanation: Sunlight drives reactions of NOx and VOCs forming oxidants such as ozone.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

9. A major oxidant present in photochemical smog is:

  • A. Nitrogen
  • B. Helium
  • C. Ozone
  • D. Hydrogen
Answer: C
Explanation: Ground-level ozone is a key photochemical-smog component.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

10. Classical reducing smog is strongly associated with:

  • A. Methane only
  • B. SO2 and particulates
  • C. O3 only
  • D. CFCs only
Answer: B
Explanation: Sulfurous smog arises from coal combustion, SO2 and particulate matter.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

11. Acid rain is mainly associated with atmospheric oxidation of:

  • A. SO2 and NOx
  • B. O2 and N2
  • C. CH4 and H2
  • D. He and Ne
Answer: A
Explanation: Sulfur and nitrogen oxides form sulfuric and nitric acids.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

12. Acid rain can damage limestone monuments because acids react with:

  • A. SiO2 only
  • B. NaCl only
  • C. Graphite
  • D. CaCO3
Answer: D
Explanation: Carbonate stone is attacked by acidic precipitation.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

13. Carbon monoxide is dangerous because it binds strongly to:

  • A. Silica
  • B. NaCl
  • C. Haemoglobin
  • D. Cellulose
Answer: C
Explanation: CO forms carboxyhaemoglobin and impairs oxygen transport.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

14. Particulate matter pollution can directly affect the:

  • A. Ocean salinity only
  • B. Respiratory system
  • C. Atomic nucleus only
  • D. Magnetic field only
Answer: B
Explanation: Fine particles penetrate the respiratory tract.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

15. Catalytic converters in automobiles help reduce emissions of:

  • A. CO, hydrocarbons and NOx
  • B. Only O2
  • C. Only N2
  • D. Only water vapour
Answer: A
Explanation: Modern catalysts oxidise CO/hydrocarbons and reduce nitrogen oxides.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

16. Lead-free petrol was promoted partly to reduce environmental exposure to:

  • A. Calcium compounds
  • B. Sodium chloride
  • C. Silica
  • D. Lead compounds
Answer: D
Explanation: Tetraethyl lead historically caused significant lead pollution.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

17. BOD is a measure related to the amount of oxygen required by:

  • A. Ozone formation
  • B. Only fish respiration
  • C. Microorganisms decomposing biodegradable organic matter
  • D. Metals dissolving in water
Answer: C
Explanation: Biochemical oxygen demand reflects microbial oxygen consumption.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

18. A high BOD value generally indicates:

  • A. High dissolved oxygen necessarily
  • B. High biodegradable organic pollution
  • C. Exceptionally pure water
  • D. No microorganisms
Answer: B
Explanation: More biodegradable waste drives greater microbial oxygen demand.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

19. Eutrophication is commonly promoted by excessive input of:

  • A. Nitrate and phosphate nutrients
  • B. Noble gases
  • C. Sand only
  • D. NaCl only
Answer: A
Explanation: Nutrient enrichment stimulates excessive algal/plant growth.

WBJEE Chemistry · Environmental Chemistry · Very Very Hard

20. An algal bloom can lower dissolved oxygen after algae die because:

  • A. Photosynthesis increases forever
  • B. Water becomes distilled
  • C. Nitrogen becomes oxygen
  • D. Microbial decomposition consumes oxygen
Answer: D
Explanation: Decomposition of biomass raises oxygen demand.

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Environmental Chemistry Practice Tests

Environmental Chemistry Frequently Asked Questions

How should I prepare Environmental Chemistry for WBJEE Chemistry?

Revise the core concepts first, make a short list of important relationships or exceptions, and then solve chapter-focused MCQs while reviewing every error.

How can ChemNexa help with Environmental Chemistry practice?

This page provides public sample questions and links to published ChemNexa tests so you can combine quick revision with structured practice.

What should I do after getting an MCQ wrong?

Identify whether the mistake came from a concept gap, calculation, unit, sign, wording or memory error, review that point, and then attempt a similar question again.

Continue with another chapter to build connected concepts and strengthen your overall Chemistry preparation.

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