Chapter 13: Environmental Chemistry – Air Exercise
Explore detailed solutions to Chapter 13: Environmental Chemistry – Air for Federal Board students. Includes multiple-choice answers, short and long questions with explanations on air pollution, greenhouse gases, acid rain, ozone depletion, and measures to reduce pollution. Perfect for exam preparation and understanding environmental chemistry concepts.
Multiple Choice Questions
(i) What is a primary source of air pollution?
- Answer: (a) Fossil fuel combustion.
Explanation: Burning fossil fuels releases harmful gases like CO₂, SO₂, and NOx, which significantly contribute to air pollution.
(ii) Which gas is primarily responsible for the greenhouse effect?
- Answer: (c) Carbon dioxide (CO₂).
Explanation: CO₂ traps heat in the Earth’s atmosphere, leading to global warming and climate change.
(iii) Nitrogen oxide (NO₂) is NOT a greenhouse gas.
- Answer: (b) Water vapor (H₂O).
Explanation: While water vapor acts as a greenhouse gas, its effect is considered natural and not directly linked to human activities.
(iv) Which is a major component of smog that poses risks to humans?
- Answer: (a) Sulfur dioxide (SO₂).
Explanation: Sulfur dioxide combines with other particles to form harmful smog, impacting respiratory health.
(v) Acid rain is primarily caused by the emission of:
- Answer: (c) Sulfur dioxide (SO₂).
Explanation: SO₂ reacts with water vapor in the atmosphere to form sulfuric acid, which falls to the ground as acid rain.
Short-Answer Questions
1. What is the difference between global warming and climate change?
- Global warming refers to the rise in Earth’s average temperature due to increased levels of greenhouse gases like CO₂ and CH₄.
- Climate change encompasses global warming and includes long-term changes in weather patterns, sea levels, and ecosystems caused by these temperature shifts.
2. Describe the health effects of air pollution.
- Air pollution causes respiratory diseases like asthma and bronchitis.
- It increases the risk of cardiovascular problems, lung cancer, and strokes.
- Particulate matter (PM2.5) and toxic gases like SO₂ and NO₂ impair lung function and reduce life expectancy.
3. What are the major greenhouse gases, and how do they affect the Earth?
- Major Greenhouse Gases:
- Carbon dioxide (CO₂)
- Methane (CH₄)
- Nitrous oxide (N₂O)
- Chlorofluorocarbons (CFCs)
- Effects:
- Trap heat in the atmosphere, increasing global temperatures.
- Lead to melting glaciers, rising sea levels, and extreme weather events.
4. Define acid rain and its environmental impacts.
- Definition: Acid rain forms when sulfur dioxide (SO₂) and nitrogen oxides (NOx) react with water vapor to form acidic compounds, which fall to the ground as precipitation.
- Impacts:
- Damages forests and crops by altering soil pH.
- Harms aquatic ecosystems by increasing water acidity, killing fish and plants.
- Erodes buildings and monuments, especially those made of limestone or marble.
5. What are some measures to reduce air pollution?
- Shift to renewable energy sources like solar and wind power.
- Use public transportation and reduce the use of private vehicles.
- Promote afforestation and protect existing forests.
- Implement stricter regulations for industries to reduce emissions of pollutants like CO₂, NO₂, and SO₂.
Long-Answer Questions
6. Discuss the role of environmental chemistry in addressing air pollution.
Environmental chemistry helps us understand the composition of air and the reactions occurring within the atmosphere. By studying pollutants like CO₂, SO₂, and NO₂, scientists can develop technologies such as scrubbers and catalytic converters to minimize emissions. Research in this field aids in crafting policies for cleaner air and reducing human impact on climate change.
7. Evaluate the causes and effects of ozone layer depletion.
- Causes:
- Release of chlorofluorocarbons (CFCs) from aerosols, refrigerants, and solvents.
- UV light breaks CFCs into chlorine atoms, which destroy ozone molecules.
- Effects:
- Increased UV radiation reaching Earth, leading to skin cancer and cataracts in humans.
- Harmful effects on marine ecosystems, particularly plankton.
- Reduced crop yields and damage to plants due to UV exposure.
8. Suggest steps to minimize the harmful effects of air pollution on health and the environment.
- Regularly monitor air quality and avoid outdoor activities during high pollution levels.
- Switch to energy-efficient appliances and vehicles.
- Promote recycling and reduce waste incineration.
- Create awareness campaigns to educate the public on the dangers of air pollution and methods to combat it.
