CBSE Class 11 Chemistry Chapter 14: Environmental Chemistry NCERT Solutions

Reviewed by NCERT Help Editorial Team · Updated on 29 Jul 2026

NCERT Solutions PDF Class 11 PDF

CBSE Class 11 Chemistry Chapter 14: Environmental Chemistry introduces the fundamental concepts of environmental chemistry, focusing on the chemical aspects of our surroundings. It explores the various components of the environment and the chemical reactions that occur within them. The chapter details different types of pollution, such as air pollution, water pollution, and soil pollution, explaining their causes, effects, and the chemical species involved. Specific attention is given to tropospheric pollution, discussing the impact of gases like sulfur oxides, nitrogen oxides, carbon monoxide, and hydrocarbons. The formation and consequences of acid rain, the mechanisms behind smog, and the health implications of air pollutants are thoroughly examined. Furthermore, the chapter elaborates on the greenhouse effect, identifying the primary greenhouse gases like carbon dioxide, methane, and chlorofluorocarbons, and their contribution to global warming. Understanding these environmental issues through a chemical lens is crucial for developing sustainable solutions.

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Board	CBSE
Class	Class 11
Subject	Chemiry
Session	2026
Language	English
Type	NCERT Solutions
Chapter	Chapter 14: Environmental Chemistry

Chapter summary

Chapter 14, Environmental Chemistry, focuses on the chemical aspects of environmental pollution. It covers the definition of environmental chemistry, details tropospheric pollution with its major gaseous and particulate pollutants, explains the formation and impact of acid rain, and discusses the role of carbon monoxide and carbon dioxide. The chapter also identifies the primary greenhouse gases responsible for global warming. These NCERT Solutions offer clear explanations of these critical environmental concepts.

Learning outcomes

Define environmental chemistry and its scope.
Identify and explain the causes and effects of tropospheric pollution.
Understand the formation and consequences of acid rain.
Differentiate between the toxicity of carbon monoxide and carbon dioxide.
List and explain the gases contributing to the greenhouse effect.

Topics covered

Paper topics

Environmental Chemistry Definition
Tropospheric Pollution
Gaseous Pollutants (SOx, NOx, CO, Hydrocarbons)
Acid Rain
Particulate Pollutants
Smog (Classical and Photochemical)
Greenhouse Effect
Greenhouse Gases (CO2, CH4, H2O, N2O, O3, CFCs)

Important topics

Tropospheric Pollution
Acid Rain Formation and Effects
Carbon Monoxide vs. Carbon Dioxide Toxicity
Greenhouse Effect and Major Gases

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Questions and Solutions

Question 14.1

Define environmental chemistry.

Solution: Environmental chemistry is the scientific field dedicated to studying the chemical and biochemical processes that occur naturally in the environment. It encompasses the investigation of the origin, movement, reactions, impacts, and ultimate fate of various chemical substances within different environmental spheres like the atmosphere, hydrosphere, and lithosphere.

Question 14.2

Explain tropospheric pollution in 100 words.

Solution: Tropospheric pollution refers to the contamination of the Earth's lowest atmospheric layer, the troposphere, by undesirable substances. Key pollutants include oxides of sulfur (SO2, SO3), nitrogen (NO, NO2), carbon (CO, CO2), and hydrocarbons. Burning fossil fuels releases SO2 and NO, which react with atmospheric oxygen and water to form sulfuric acid (H2SO4) and nitric acid (HNO3), leading to acid rain. Acid rain damages ecosystems and causes respiratory issues. Hydrocarbons contribute to smog and can be carcinogenic. Carbon monoxide (CO) is highly toxic as it reduces blood's oxygen-carrying capacity. Carbon dioxide (CO2), while not acutely toxic, contributes to global warming by trapping infrared radiation. Particulate matter like smoke and dust can block nasal passages and cause respiratory problems. Smog, a combination of smoke and fog, reduces visibility and irritates the eyes and lungs.

$2SO_{2(g)} + O_{2(g)} + 2H_2O_{(f)} \longrightarrow 2H_2SO_{4(aq)}$

$4NO_{2(g)} + O_{2(g)} + 2H_2O_{(l)} \longrightarrow 4HNO_{3(ag)}$

Question 14.3

Carbon monoxide gas is more dangerous than carbon dioxide gas. Why?

Solution: Carbon monoxide (CO) is significantly more dangerous than carbon dioxide (CO2) primarily due to its effect on oxygen transport in the blood. While both gases are products of incomplete combustion, CO is poisonous because it binds to hemoglobin (Hb) in red blood cells to form carboxyhemoglobin (COHb). This complex is much more stable than the oxyhemoglobin (HbO2) complex formed with oxygen. Even at low concentrations (3-4%), COHb formation drastically reduces the amount of oxygen that blood can carry to the body's tissues. This oxygen deprivation can lead to headaches, visual disturbances, nervousness, cardiovascular problems, and even death at higher concentrations. Carbon dioxide, on the other hand, is not directly toxic at typical environmental concentrations; it only becomes harmful at extremely high levels.

Question 14.4

List gases which are responsible for greenhouse effect.

Solution: The primary gases responsible for the greenhouse effect, which traps heat in the Earth's atmosphere and contributes to global warming, are:

Carbon dioxide (CO2)
Methane (CH4)
Water vapor (H2O)
Nitrous oxide (N2O)
Ozone (O3)
Chlorofluorocarbons (CFCs)

Common mistakes

Confusing the relative toxicity of CO and CO2.
Not fully understanding the chemical reactions leading to acid rain.
Incomplete listing of greenhouse gases.

Revision tips

Focus on understanding the chemical reactions involved in pollution.
Memorize the list of major pollutants and greenhouse gases.
Review the definitions and key terms related to environmental chemistry.
Practice explaining the effects of pollution in your own words.

Practice MCQs

Q1. What is the primary focus of environmental chemistry?

Q2. Which of the following is a major gaseous pollutant contributing to acid rain?

Q3. Why is carbon monoxide (CO) considered more dangerous than carbon dioxide (CO2)?

Q4. Which of these is NOT typically listed as a major greenhouse gas?

Q5. Photochemical smog can cause:

Frequently asked questions

What is environmental chemistry?

Environmental chemistry is the branch of chemistry that studies the effects of human activities on the environment, focusing on chemical and biochemical processes occurring in nature, their origins, transport, reactions, effects, and fates.

What causes acid rain?

Acid rain is primarily caused by the release of sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere from burning fossil fuels. These gases react with water, oxygen, and other chemicals to form sulfuric and nitric acids.

Why is carbon monoxide more dangerous than carbon dioxide?

Carbon monoxide is more dangerous because it binds to hemoglobin in the blood much more strongly than oxygen, forming carboxyhemoglobin. This significantly reduces the blood's ability to transport oxygen to the body's tissues, potentially leading to death.

What are the main greenhouse gases?

The main greenhouse gases include carbon dioxide (CO2), methane (CH4), water vapor (H2O), nitrous oxide (N2O), ozone (O3), and chlorofluorocarbons (CFCs).

How do these NCERT Solutions help students?

These solutions provide clear, step-by-step explanations for each question in Chapter 14, helping students understand complex concepts like pollution, acid rain, and the greenhouse effect, aiding in exam preparation.

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