RBSE Solutions Class 11 Chemistry Chapter 14 Environmental Chemistry

RBSE Class 11 Chemistry Chapter 14 Text Book Questions

RBSE Class 11 Chemistry Chapter 14 Multiple Choice Questions

Question 1. PAN means:
(a) Peroxy Aldehyde Nitrate
(b) Peroxy Ammonium Nitrate
(c) Peroxy acetyl Nitrate
(d) None of the options
Answer: (c) Peroxy acetyl Nitrate
In simple words: PAN stands for Peroxy acetyl Nitrate, which is a chemical compound found in smog, formed from air pollution and sunlight.

🎯 Exam Tip: Remember common acronyms related to environmental chemistry, as they are often tested directly.

Question 3. What is the reason of increase in temperature?
(a) Acid rain
(b) Nuclear Accidents
(c) Increase in heat at faster rate
(d) Green House Effect
Answer: (d) Green House Effect
In simple words: The rise in Earth's temperature is mainly caused by the Greenhouse Effect, where certain gases trap heat in the atmosphere.

🎯 Exam Tip: Distinguish between the causes and effects of various environmental phenomena like acid rain and the greenhouse effect.

Question 4. CFC's are used in :
(a) Refrigerants
(b) Plastic formation
(c) In electrical appliances
(d) All of the options
Answer: (a) Refrigerants
In simple words: CFCs are mainly used in cooling systems, like refrigerators and air conditioners, as refrigerants.

🎯 Exam Tip: Know the primary applications of common pollutants like CFCs and their environmental impact, especially on the ozone layer.

Question 5. Which of the following is not a green house gas?
(a) \( \text{CO}_2 \)
(b) \( \text{CH}_4 \)
(c) \( \text{COCl}_2 \)
(d) \( \text{N}_2\text{O} \)
Answer: (c) COCl\( _2 \)
In simple words: Carbon dioxide, methane, and nitrous oxide are all greenhouse gases, but phosgene (\( \text{COCl}_2 \)) is not.

🎯 Exam Tip: Memorize the major greenhouse gases and be able to identify which substances are not included in this group.

RBSE Class 11 Chemistry Chapter 14 Very Short Answer Type Questions

Question 7. What do you mean by Green House Effect?
Answer: The Greenhouse Effect is when man-made carbon dioxide and other gases trap heat in the Earth's atmosphere. This process causes the overall temperature of the Earth to rise, making the planet warmer.
In simple words: The Greenhouse Effect is the warming of the Earth when gases like carbon dioxide in the air trap heat.

🎯 Exam Tip: Define the Greenhouse Effect clearly and mention the key gases involved in your explanation.

Question 8. Which gases are responsible for acid rain?
Answer: The gases mainly responsible for acid rain are oxides of nitrogen and oxides of sulphur. These gases react with water in the atmosphere to form acids, which then fall as acid rain.
In simple words: Acid rain is caused by gases like nitrogen oxides and sulfur oxides.

🎯 Exam Tip: Identify the specific oxides of nitrogen and sulfur as the primary culprits behind acid rain.

Question 9. Which are the main gases which affect Ozone layer?
Answer: The main gases that harm the ozone layer are chlorofluorocarbons (CFCs), also known as Freons, and other related hydrocarbon compounds. These chemicals break down ozone molecules, thinning the ozone layer.
In simple words: Chlorofluorocarbons (CFCs) and some other hydrocarbons damage the ozone layer.

🎯 Exam Tip: Name chlorofluorocarbons (CFCs) specifically when discussing ozone layer depletion.

Question 10. Write the composition of smog.
Answer: Smog is primarily made up of several harmful substances. Its main components include oxides of nitrogen, various volatile organic compounds, tropospheric ozone (ground-level ozone), and PAN (Peroxy acetyl nitrate). These combine to form a hazy mixture in the air.
In simple words: Smog is a mix of nitrogen oxides, organic chemicals, ozone, and PAN.

🎯 Exam Tip: List the key chemical components of smog, including both primary and secondary pollutants.

Question 11. Amount of which gas is maximum in atmosphere?
Answer: Nitrogen is the gas present in the largest amount in the Earth's atmosphere, making up approximately 78.09% of its composition.
In simple words: Nitrogen gas is the most common gas in our atmosphere, making up about 78%.

🎯 Exam Tip: Remember the approximate percentage of nitrogen in the atmosphere.

Question 13. Which gases are responsible for green house effect?
Answer: The primary gases responsible for the greenhouse effect are carbon dioxide, methane, ozone, nitrous oxide, chlorofluorocarbons, and water vapour. These gases trap heat in the atmosphere, leading to global warming.
In simple words: Carbon dioxide, methane, ozone, nitrous oxide, CFCs, and water vapour cause the greenhouse effect.

🎯 Exam Tip: List all major greenhouse gases to score full marks on this question.

Question 14. How many types of water pollution are there?
Answer: Water pollution can be categorized into many different types because water sources can be contaminated in various ways. These types include:
1. Nutrients pollution
2. Surface water pollution
3. Oxygen depletion in water
4. Ground water pollution
5. Microbiological pollution
6. Water pollution due to suspended matter
7. Chemical water pollution
8. Oil spoilage in water
In simple words: There are many kinds of water pollution, like from extra nutrients, chemicals, germs, or oil, depending on how the water gets dirty.

🎯 Exam Tip: When listing types of pollution, try to provide a diverse range of examples covering different sources and impacts.

RBSE Class 11 Chemistry Chapter 14 Long Answer Type Questions

Question 15. What are the main sources of air pollution?
Answer: The main sources of air pollution come from both natural events and human activities:
1. Natural sources:
• Volcanic eruptions release harmful gases like sulfur dioxide (\( \text{SO}_2 \)), hydrogen sulfide (\( \text{H}_2\text{S} \)), and carbon monoxide (\( \text{CO} \)).
• Forest fires release smoke and different trace gases.
• Organic matter decaying releases methane (\( \text{CH}_4 \)).
• Pollen grains, fungal spores, and bacteria also contribute.
2. Man-made sources:
• Automobile exhausts from vehicles release pollutants.
• Industrialization leads to many types of emissions.
• Agricultural activities, like using fertilizers and pesticides, also cause pollution.
In simple words: Air pollution comes from things like volcanoes, forest fires, rotting plants, car fumes, factories, and farm work.

🎯 Exam Tip: Categorize air pollution sources into natural and man-made for a comprehensive answer, giving specific examples for each.

Question 16. How smog formed and what are its effect?
Answer: Smog, specifically photochemical smog, forms when sunlight reacts with nitrogen oxides and hydrocarbons. These pollutants are released into the air from vehicles and factories. The process involves several chemical reactions:
\( \text{NO}_2(\text{g}) \xrightarrow{h\nu} \text{NO}(\text{g}) + \text{O}(\text{g}) \)
\( \text{O}(\text{g}) + \text{O}_2(\text{g}) \longrightarrow \text{O}_3(\text{g}) \)
\( \text{NO}(\text{g}) + \text{O}_3(\text{g}) \longrightarrow \text{NO}_2(\text{g}) + \text{O}_2(\text{g}) \)
Ozone (\( \text{O}_3 \)) is a toxic gas, and both \( \text{NO}_2 \) and \( \text{O}_3 \) are strong oxidizing agents. They can react with hydrocarbons from vehicles to create chemicals such as formaldehyde, acrolein, and PAN (peroxy acetyl nitrate). For example:
\( 3\text{CH}_4 + 2\text{O}_3 \longrightarrow 3\text{HCHO} + 3\text{H}_2\text{O} \)
(Formaldehyde)
The formation of Acrolein and PAN can also be represented as:
\( \text{CH}_2=\text{CH}-\text{CHO} \)
(Acrolein)
\( \text{CH}_3-\text{C}(=\text{O})-\text{O}-\text{NO}_2 \)
(Peroxy acetyl nitrate)

Effects of smog:
• Smog causes metals, stones, building materials, rubber, and painted surfaces to corrode or wear away.
• It irritates the eyes and nose, causing discomfort.
• High levels of smog can lead to headaches, chest pain, a dry throat, coughing, and breathing difficulties.
• It causes rubber to crack and damages plant life.
In simple words: Smog forms when sunlight mixes with car and factory pollution. It damages buildings, irritates people's eyes and lungs, and harms plants and rubber.

🎯 Exam Tip: Explain the formation of smog by highlighting the role of sunlight, nitrogen oxides, and hydrocarbons, and list at least three key effects.

Question 18. What is Green House Effect? How it affects life?
Answer: Green House Effect: The Greenhouse Effect is the gradual warming of the Earth's surface. This happens because human-made carbon dioxide and other gases create a "blanket" in the atmosphere, trapping heat. It's a natural process where the Earth holds onto some heat. The main gases causing this effect are carbon dioxide (\( \text{CO}_2 \)), methane (\( \text{CH}_4 \)), nitrous oxide (\( \text{N}_2\text{O} \)), and chlorofluorocarbons (CFCs). Among these, \( \text{CO}_2 \) is the most common gas that drives this effect.

Consequences of Green House Effect:
The effects of the Greenhouse Effect are harmful to the environment:
• The Earth's temperature goes up because of the greenhouse effect.
• This can cause glaciers and polar ice caps to melt.
• Sea levels may rise, which leads to floods.
• It impacts the growth and production of food crops.
• Fertile land can become barren, and aquatic life in water bodies is severely affected.
In simple words: The Greenhouse Effect warms the Earth due to gases trapping heat. This causes temperatures to rise, ice to melt, sea levels to go up, and harms crops and water life.

🎯 Exam Tip: Clearly define the Greenhouse Effect and provide a range of consequences, including impacts on climate, ecosystems, and human activities.

Question 20. What is the impact of water pollution on plants?
Answer: Water pollution negatively affects plants by leading to lower crop yields. When water is contaminated, the quality and quantity of crops grown using that water are poor. This directly decreases the amount of harvest. Water pollution can also introduce toxins that inhibit plant growth or kill plants outright.
In simple words: Water pollution makes plants grow poorly and reduces the amount of food harvested from them.

🎯 Exam Tip: Focus on the direct impact of water pollution on plant health and agricultural productivity.

Question 21. What are industrial effluents and how it pollutes the environment?
Answer: Industrial effluents are the liquid waste materials discharged from industries. These include both organic and inorganic chemical pollutants that come from places like breweries, tanneries, paper mills, and other factories. These effluents cause water pollution. When they enter water bodies, they increase the biological oxygen demand (B.O.D.). B.O.D. is the amount of oxygen that tiny living things (microorganisms) need to break down the organic stuff in water. More organic matter in the water means a higher B.O.D., which uses up oxygen that fish and other aquatic life need to survive.
In simple words: Industrial effluents are chemical wastes from factories that pollute water. They make microorganisms use up more oxygen in the water, harming aquatic life.

🎯 Exam Tip: Define industrial effluents and explain how they impact water quality, specifically linking them to biological oxygen demand (B.O.D.).

RBSE Class 11 Chemistry Chapter 14 Long Answer Type Questions

Question 22. What are the sources of water pollution? What steps could be taken to prevent water pollution?
Answer: Sources of water pollution:
Water pollution comes from various sources, which can be grouped as follows:
1. Natural sources:
• Pathogens, which include harmful bacteria and other tiny organisms.
2. Man-made sources:
• Domestic sewage, like rotting fruits, soaps, and detergents from homes.
• Municipal sewage, which is waste released from houses, public toilets, and bathing areas.
• Industrial wastes.
• Industrial effluents, which are liquid discharges from factories.
• Agricultural discharge, such as fertilizers and pesticides.

Prevention of water pollution:
To stop water pollution, we can take the following steps:
• Do not bathe or wash clothes in rivers and streams, and do not dispose of untreated sewage in water bodies.
• Use pesticides and fertilizers carefully and only when needed.
• Treat wastewater before reusing it for irrigation or municipal purposes.
• Regularly check and monitor water bodies for pollution.
• Use wastewater treatment plants or other facilities to properly manage waste before discharge.
In simple words: Water pollution comes from germs, house waste, factory waste, and farm chemicals. We can stop it by not polluting rivers, using fewer chemicals, treating wastewater, and monitoring water quality.

🎯 Exam Tip: Divide your answer into sources and prevention methods, providing a few clear examples for each category.

Question 23. Write short note on Industrial pollution.
Answer: Pollutants from industries cause air, water, and soil pollution. The type of industrial waste depends on the specific industry. Most wastes come from industrial effluents, which contain organic substances, inorganic salts, solids, and fertilizers. These pollutants are released into the environment, sometimes along with heat, bacteria, and disease-causing agents. For example, rubber industries release soluble wastes containing chloride. Steel industries, like those in Bhiwadi, release acids, phenol, cyanogen, limestone, and oily substances as pollutants. Oil refineries contribute acids, alkalis, resins, and petro-oils. Fertilizer industries release substances like ammonium fluoride and potassium nitrate. All these toxic substances harm the environment.
In simple words: Industrial pollution comes from factories releasing various wastes like chemicals, salts, and organic matter into the air, water, and soil, harming the environment.

🎯 Exam Tip: Explain that industrial pollution varies by industry type and provide examples of different pollutants released from specific industries.

Question 26. What is Green Chemistry and what are its contributions in prevention of pollution?
Answer: Green Chemistry, also known as Sustainable Chemistry, is a field of chemistry and chemical engineering. It focuses on designing chemical products and processes that minimize or eliminate the use and creation of harmful substances. This approach aims to reduce environmental pollution.

Green Chemistry was first suggested around 1990 as a way to control pollution. It promotes using chemicals, reactants, and solvents that are not harmful to humans or the environment. It ensures that chemical reactions are efficient while also reducing their toxic impact.

Contributions of Green Chemistry in Prevention of pollution:
Green Chemistry is a philosophy that aims to change current practices to prevent future problems. Its contributions include:
• Developing aqueous and non-aqueous solvents that are safe for humans and don't pollute the environment.
• Encouraging the use of biofuels like biodiesel and hydrogen in vehicles to reduce emissions.
• Focusing on processes that release the smallest possible amount of waste.
• Using enzymes as catalysts in manufacturing processes, such as for antibiotics, which are less harmful than traditional methods.
• Discovering methods to reduce pollutants like \( \text{SO}_2 \) to sulfur using green chemistry principles:
\( \text{C} + \text{SO}_2 \xrightarrow{800^\circ\text{C}} \text{CO}_2 + \text{S} \)
• Using limestone to absorb \( \text{SO}_2 \) gas:
\( 2\text{CaCO}_3 + 2\text{SO}_2 + \text{O}_2 \longrightarrow 2\text{CaSO}_4 + 2\text{CO}_2 \)
• Developing green chemistry-based detergents that reduce pollution.
• Using \( \text{CO}_2 \) for packing foam sheets instead of chlorofluorocarbons.
• Researching alternatives like using helium in place of petrol and diesel to stop vehicle pollution.
• Discovering new ways to produce agricultural chemicals without using poisonous materials like cyanide or formaldehyde.
In simple words: Green Chemistry designs safer chemical processes and products to reduce pollution. It helps by finding less harmful solvents, promoting biofuels, creating less waste, and developing cleaner ways to make and use chemicals, like turning sulfur dioxide into sulfur.

🎯 Exam Tip: Define green chemistry as sustainable chemistry focused on minimizing hazardous substances, and list specific examples of its contributions to pollution prevention.