NIOS Class 12 Chemistry Chapter 32 Environmental Chemistry

NIOS Class 12 Chemistry Chapter 32 Environmental Chemistry Solutions English Medium As Per New Syllabus to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Chemistry Chapter 32 Environmental Chemistry Notes in English and select need one. NIOS Class 12 Chemistry Solutions English Medium Download PDF. NIOS Study Material of Class 12 Chemistry Notes Paper Code: 313.

NIOS Class 12 Chemistry Chapter 32 Environmental Chemistry

Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Chemistry Notes, NIOS Senior Secondary Course Chemistry Solutions in English for All Chapter, You can practice these here.

Environmental Chemistry

Chapter: 32

Module VIII: Chemistry in Everyday Life

INTEXT QUESTIONS 32.1

1. Define environment.

Ans: The air, water, earth and living beings in a joint form is called the environment.

2. What are the two components of the environment?

Ans: There are two components of the environment namely biotic and abiotic.

3. List three biotic components?

Ans: Living organisms such as plants, animals, microbes, etc.

4. How do CFCs affect the ozone layer?

Ans: Causes holes in the ozone layer.

5. What are the different segments of the environment?

Ans: Atmosphere, biosphere, hydrosphere and lithosphere.

INTEXT QUESTIONS 32.2

1. Define a pollutant.

Ans: Any substance which is present in its excess concentration such as CO₂, CO, SO₂.

2. Name two sources of natural pollution.

Ans: Volcenic eruptions and run-off from surface mines.

3. Define a secondary pollutant.

Ans: Secondary pollutants are the products of reaction between the primary pollutant and the normal environmental constituents.

4. What do you mean by environmental pollution?

Ans: Environmental pollution is the deterioration or unclean objectionable conditions in the quality of natural resources such as air water and soil because of the action or presence of unwanted substances in undesirable concentration.

INTEXT QUESTIONS 32.3

1. What is atmospheric pollution?

Ans: undesirable level of undesirable and harmful substances in the atmosphere

2. Name two particulate pollutants.

Ans: soot, fluoride, Pb dust, NaCl (any two)

3. Name two gaseous pollutants?

Ans: SO₂, CO₂, CO, NH3, H₂S (any two).

4. Name one source which causes pollution due to methane.

Ans: methanogenic bacteria, ruminant stomach, fermentation in water logged paddy fields (any one).

5. Name two air pollutants which form photochemical smog.

Ans:  PAN and O₃.

INTEXT QUESTIONS 32.4

1. What is smog?

Ans: Smog is a mixture of smoke and fog.

2. Name two photochemical oxidants.

Ans: Ozone (O₃) and Peroxyacetyl Nitrate (PAN).

3. Name two gases which form acid rain.

Ans: Sulphur dioxide (SO₂) and Nitrogen oxides (NOₓ).

4. Mention any four greenhouse gases.

Ans: Carbon dioxide (CO₂), Methane (CH₄), Nitrogen dioxide (NO₂), CFCs.

5. What are the sources of freons and halons in air?

Ans: Refrigerators, air conditioners, aerosol sprays, and fire extinguishers.

6. What effect does acid rain have on marble statues?

Ans: Acid rain corrodes and damages marble statues.

7. Mention one measure to control air pollution.

Ans: Use clean and renewable fuels and reduce the use of polluting fuels.

INTEXT QUESTIONS 32.5

1. Define water pollution.

Ans: Water pollution is the contamination of water bodies like rivers, lakes, and groundwater by harmful substances, making the water unsafe for living organisms and human use.

2. List any three anthropogenic sources of water pollution.

Ans: (i) Industrial wastes and chemicals.

(ii) Domestic sewage and wastewater.

(iv) Agricultural runoff (fertilizers and pesticides).

3. List the parameters indicating water pollution.

Ans: (i) Dissolved oxygen (DO).

(ii) Biochemical oxygen demand (BOD).

(iii) Chemical oxygen demand (COD).

(iv) pH value.

(v) Presence of harmful chemicals or microbes.

INTEXT QUESTIONS 32.6

1. Define eutrophication.

Ans: Eutrophication is the excessive enrichment of water bodies, like lakes or rivers, with nutrients such as nitrogen and phosphorus. 

This leads to:

(i) Algal blooms.

(ii) Oxygen depletion.

(iii) Reduced water quality.

(iv) Harm to aquatic life.

It’s often caused by runoff from agricultural fertilizers, sewage, or industrial waste.

2. Why does aquatic life get killed in an eutrophied pond?

Ans: In an eutrophied pond, excess nutrients cause rapid growth of algae. When algae die, bacteria decompose them and use up dissolved oxygen. Due to lack of oxygen, fishes and other aquatic organisms die.

3. What is the significance of BOD?

Ans: BOD (Biochemical Oxygen Demand) indicates the amount of oxygen required by microorganisms to decompose organic matter in water. A high BOD value means high water pollution and poor water quality.

4. What is biomagnification?

Ans: Biomagnification is the process where toxic substances, like pollutants or chemicals, become more concentrated as they move up the food chain. This happens because organisms at higher trophic levels consume many organisms from lower levels, accumulating higher amounts of the substance.

For example, mercury levels can be low in small fish but become much higher in larger fish that eat them, posing health risks to humans and wildlife who consume these larger fish.