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Environmental Chemistry WBCHSE Class 11 MCQ & Practice Questions

Practice Environmental Chemistry MCQs for WBCHSE Class 11 Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

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Environmental Chemistry Revision Guide for WBCHSE Class 11 Chemistry

Environmental Chemistry is part of WBCHSE Class 11 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 WBCHSE Class 11 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.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

1. The lowest layer of the atmosphere is:

  • A. Mesosphere
  • B. Thermosphere
  • C. Troposphere
  • D. Stratosphere
Answer: C
Explanation: The troposphere extends upward from Earth's surface and contains most atmospheric mass.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

2. Most weather phenomena occur in the:

  • A. Exosphere
  • B. Troposphere
  • C. Stratosphere
  • D. Mesosphere
Answer: B
Explanation: Clouds and weather are concentrated in the troposphere.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

3. The ozone layer is concentrated mainly in the:

  • A. Stratosphere
  • B. Troposphere
  • C. Mesosphere
  • D. Lithosphere
Answer: A
Explanation: Stratospheric ozone absorbs much harmful ultraviolet radiation.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

4. An important natural greenhouse gas is:

  • A. O2
  • B. N2
  • C. He
  • D. CO2
Answer: D
Explanation: Carbon dioxide absorbs outgoing infrared radiation and contributes to the greenhouse effect.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

5. Which gas is a major anthropogenic greenhouse gas?

  • A. Ar
  • B. He
  • C. CO2
  • D. Ne
Answer: C
Explanation: Human activities have substantially increased atmospheric CO2.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

6. Methane contributes to:

  • A. Removal of all aerosols
  • B. Greenhouse warming
  • C. Ozone formation only in stratosphere
  • D. Acid rain as the main cause
Answer: B
Explanation: Methane is an effective greenhouse gas.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

7. Global warming refers to a long-term rise in:

  • A. Earth's average surface temperature
  • B. Ocean salinity only
  • C. Atmospheric nitrogen percentage only
  • D. Earth's mass
Answer: A
Explanation: Enhanced greenhouse forcing raises global mean temperature.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

8. The principal gases responsible for acid rain include:

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

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

9. Acid rain can damage:

  • A. Only deep ocean trenches
  • B. Nothing made of carbonate
  • C. Aquatic ecosystems, soils and monuments
  • D. Only noble gases
Answer: C
Explanation: Acid deposition affects ecosystems and attacks materials such as limestone and marble.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

10. Photochemical smog is favoured by:

  • A. Absence of sunlight
  • B. Sunlight, NOx and hydrocarbons/VOCs
  • C. Only nitrogen and argon
  • D. Heavy rain only
Answer: B
Explanation: Sunlight drives reactions involving nitrogen oxides and volatile organics.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

11. A major component of photochemical smog is:

  • A. Ozone
  • B. Helium
  • C. Hydrogen
  • D. Nitrogen gas only
Answer: A
Explanation: Ground-level ozone is a key secondary photochemical pollutant.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

12. Classical reducing smog is associated strongly with:

  • A. Ozone and PAN only
  • B. Helium and neon
  • C. Hydrogen and oxygen
  • D. SO2 and particulate matter
Answer: D
Explanation: Sulfurous smog forms under cool, humid conditions with sulfur dioxide and smoke.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

13. PAN in photochemical smog stands for:

  • A. Peroxide ammonia nitrite
  • B. Phosphorus acetate nitrate
  • C. Peroxyacetyl nitrate
  • D. Polyatomic acid nitrate
Answer: C
Explanation: PAN is peroxyacetyl nitrate, a secondary photochemical pollutant.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

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

  • A. Calcium carbonate
  • B. Haemoglobin
  • C. Cellulose
  • D. Chlorophyll in humans
Answer: B
Explanation: CO forms carboxyhaemoglobin and reduces oxygen transport.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

15. Particulate matter can harm health mainly by affecting the:

  • A. Respiratory system
  • B. Atomic nucleus
  • C. Bone mineral only
  • D. DNA bases exclusively
Answer: A
Explanation: Fine particles can penetrate the respiratory tract.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

16. A primary pollutant is one that is:

  • A. Always formed only in sunlight
  • B. Never emitted directly
  • C. Necessarily harmless
  • D. Emitted directly from a source
Answer: D
Explanation: Primary pollutants enter the environment directly from identifiable sources.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

17. A secondary pollutant is:

  • A. Always a metal
  • B. Always biodegradable
  • C. Formed in the environment by reactions of primary pollutants
  • D. Always emitted directly
Answer: C
Explanation: Secondary pollutants such as ozone can form through atmospheric chemistry.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

18. Stratospheric ozone protects life by absorbing much:

  • A. Sound
  • B. UV radiation
  • C. Visible red light only
  • D. Radio waves
Answer: B
Explanation: Ozone strongly absorbs biologically harmful UV radiation.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

19. Ozone depletion has been strongly associated with:

  • A. CFCs
  • B. CO2 alone
  • C. N2
  • D. Water vapour only
Answer: A
Explanation: CFC-derived chlorine radicals catalyse ozone destruction.

WBCHSE Class 11 Chemistry · Environmental Chemistry · Very Hard

20. CFCs release ozone-destroying radicals after exposure to:

  • A. Visible light in soil only
  • B. Sound waves
  • C. Magnetic fields
  • D. UV radiation in the stratosphere
Answer: D
Explanation: High-energy UV photolyses CFCs and liberates chlorine radicals.

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Environmental Chemistry Practice Tests

Environmental Chemistry Frequently Asked Questions

How should I prepare Environmental Chemistry for WBCHSE Class 11 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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