MP Board Class 11th Chemistry Solutions Chapter 14 Environmental Chemistry

In this article, we will share MP Board Class 11th Chemistry Solutions Chapter 12 Organic Chemistry: Some Basic Principles and Techniques Pdf, These solutions are solved by subject experts from the latest edition books.

MP Board Class 11th Chemistry Solutions Chapter 14 Environmental Chemistry

MP Board Class 11 Chemistry Environmental Chemistry Textbook Questions and Answers

Question 1.
Define environmental chemistry.
Solution.
Environmental chemistry is defined as the branch of science w’hich deals with the chemical processes occuring in the environment. It involves the study of origin, transport, reactions, effects and the fates of chemical species in the environment.

Question 2.
Explain tropospheric pollution in 100 words.
Solution.
Tropospheric pollution occurs due to the presence of undesirable gases and the solid particles in the air. The major gaseous and the particulate pollutants present in the troposphere are as follows:
Gaseous air pollutants. These include mainly oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂) and oxides of carbon (CO, CO₂) in addition to hydrogen sulphide (H₂S), hydrocarbons, ozone and other oxidants.
Particulate pollutants. These include dust, mist, fumes, smoke, smog, etc.

Question 3.
Carbon monoxide gas is more dangerous than carbon dioxide gas. Why?
Solution.
CO combines with haemoglobin to form a complex entity, carboxyhaemoglobin which is about 300 times more stable than oxy-haemoglobin. In blood, when the concentration of carboxyhaemoglobin reaches 3-4%, the oxygen-carrying capacity of the blood is significantly reduced. In other words, the body becomes oxygen-starved. This results into headache, nervousness, cardiovascular disorder, weak eye-sight etc.

Question 4.
Which gases are responsible for greenhouse effect? List some of them.
Solution.
The main gas responsible for greenhouse effect is CO₂. Other greenhouse gases are methane, nitrous oxide, water vapours, chlorofluorocarbons (CFC’s) and ozone.

Question 5.
Statues and monuments in India are affected by acid rain. How?
Solution.
The air around the statues and monuments in India contains fairly high levels of the oxides of sulphur and nitrogen. This is mainly due to a large number of industries and power plants in the nearby areas. The use of poor quality of coal, kerosene and firewood as fuel for domestic purposes further adds to the problems. The resulting acid rain reacts with the marble of these statues and monuments.
CaCO₃ + H₂SO₄→ CaSO₄ + H₂O + CO₂
As a consequence, these monuments are being slowly eaten away and marble is gradually losing its lustre (shining) and colour.

Question 6.
What are smogs ? How are classical smog and photochemical smogs different?
Solution.
Tropospheric pollution occurs due to the presence of undesirable gases and the solid particles in the air. The major gaseous and the particulate pollutants present in the troposphere are as follows:
Gaseous air pollutants. These include mainly oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂) and oxides of carbon (CO, CO₂) in addition to hydrogen sulphide (H₂S), hydrocarbons, ozone and other oxidants.
Particulate pollutants. These include dust, mist, fumes, smoke, smog, etc. (Page 583 and 584)

Question 7.
Write down the reactions involved during the formation of photochemical smog.
Solution.
Tropospheric pollution occurs due to the presence of undesirable gases and the solid particles in the air. The major gaseous and the particulate pollutants present in the troposphere are as follows:
Gaseous air pollutants. These include mainly oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂) and oxides of carbon (CO, CO₂) in addition to hydrogen sulphide (H₂S), hydrocarbons, ozone and other oxidants.
Particulate pollutants. These include dust, mist, fumes, smoke, smog, etc. (Page 583)

Question 8.
What are the harmful effects of photochemical smog and how can they be controlled?
Solution.
Tropospheric pollution occurs due to the presence of undesirable gases and the solid particles in the air. The major gaseous and the particulate pollutants present in the troposphere are as follows:
Gaseous air pollutants. These include mainly oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂) and oxides of carbon (CO, CO₂) in addition to hydrogen sulphide (H₂S), hydrocarbons, ozone and other oxidants.
Particulate pollutants. These include dust, mist, fumes, smoke, smog, etc. (Page 584)

Question 9.
What are the reactions involved for ozone layer depletion in the atmosphere?
Solution.
Tropospheric pollution occurs due to the presence of undesirable gases and the solid particles in the air. The major gaseous and the particulate pollutants present in the troposphere are as follows:
Gaseous air pollutants. These include mainly oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂) and oxides of carbon (CO, CO₂) in addition to hydrogen sulphide (H₂S), hydrocarbons, ozone and other oxidants.
Particulate pollutants. These include dust, mist, fumes, smoke, smog, etc.

Question 10.
What do you mean by ozone hole? What are its consequences?
Solution.
Tropospheric pollution occurs due to the presence of undesirable gases and the solid particles in the air. The major gaseous and the particulate pollutants present in the troposphere are as follows:
Gaseous air pollutants. These include mainly oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂) and oxides of carbon (CO, CO₂) in addition to hydrogen sulphide (H₂S), hydrocarbons, ozone and other oxidants.
Particulate pollutants. These include dust, mist, fumes, smoke, smog, etc. (Page 585)

Question 11.
What are major causes of water pollution? Explain.
Solution.
CO combines with haemoglobin to form a complex entity, carboxyhaemoglobin which is about 300 times more stable than oxy-haemoglobin. In blood, when the concentration of carboxyhaemoglobin reaches 3-4%, the oxygen-carrying capacity of the blood is significantly reduced. In other words, the body becomes oxygen-starved. This results into headache, nervousness, cardiovascular disorder, weak eye-sight etc. (Page 586)

Question 12.
Have you ever observed any water pollution in your area? How can you control it?
Solution.
Answer on the basis of your observations.

Question 13.
What do you mean by Biochemical Oxygen Demand (BOD)?
Solution.
It is a measure of the dissolved oxygen that would be needed by micro-organisms and various chemical pollutants. CO combines with haemoglobin to form a complex entity, carboxyhaemoglobin which is about 300 times more stable than oxy-haemoglobin. In blood, when the concentration of carboxyhaemoglobin reaches 3-4%, the oxygen-carrying capacity of the blood is significantly reduced. In other words, the body becomes oxygen-starved. This results into headache, nervousness, cardiovascular disorder, weak eye-sight etc.

Question 14.
Do you observe any soil pollution in your neighbourhood? What efforts will you make for controlling the soil pollution?
Solution.
Answer on the basis of your observations.

Question 15.
What are pesticides and herbicides? Explain giving examples.
Solution.
Pesticides. These are synthetic chemical compounds which are toxic and are used in agriculture to protect the crops and plants from the pests like insects, rodents, weeds and various crop diseases. It has been established that the repeated use of pesticides give rise to pests which become resistant to that group of pesticides. As a result, these pesticides become ineffective for those pests. Earlier DDT was used as pesticide. The insects developed resistance towards DDT gradually over the years and therefore, other organic toxins such as Aldrin and Dialdrin were introduced for use as pesticides.

But these were non-biodegradable and slowly transferred to human beings through food chain causing metabolic and physiological disorders. Consequently, a new series of pesticides, organophosphates and carbamates have been introduced. These are biodegradable. However, they are severe nerve toxins and hence more harmful to humans. The insecticide industry is, now a days, engaged in developing new insecticides. Herbicides. These are the chemicals used to control weeds. Earlier, inorganic compounds such as sodium chlorate (NaClO₃) and sodium arsenite (Na₃AsO₃) were used but arsenic compounds, being toxic to mammals, are no longer preferred. Instead, organic compounds such as triazines, are now considered as better herbicides, especially for the corn-fields.

Question 16.
What do you mean by green chemistry? How will it help decrease environmental pollution?
Solution.
Tropospheric pollution occurs due to the presence of undesirable gases and the solid particles in the air. The major gaseous and the particulate pollutants present in the troposphere are as follows:
Gaseous air pollutants. These include mainly oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂) and oxides of carbon (CO, CO₂) in addition to hydrogen sulphide (H₂S), hydrocarbons, ozone and other oxidants.
Particulate pollutants. These include dust, mist, fumes, smoke, smog, etc. (Pages 589 and 590)

Question 17.
What would have happened if the greenhouse gases were totally missing in the earth’s atmosphere? Discuss.
Solution.
The solar energy radiated back from the earth surface is absorbed by the greenhouse gases (i.e., CO₂, CH₄, O₃, CFC’s and water vapour) present near the earth’s surface. They heat up the atmosphere near the earth’s surface and keep it warm. As a result, they keep the temperature of the earth constant and help in the growth of plants and existence of life on the earth. If there were no greenhouse gases, there would have no vegetation and life on the earth.

Question 18.
A large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dumping but you find an abundance of phytoplankton. Suggest a reason for the fish kill.
Solution.
Excessive phytoplankton (organic pollutants such as leaves, grass, trash, etc.) present in water is biodegradable. A large population of bacteria decomposes this organic matter in water. During this process they consume the oxygen dissolved in water. Water has already limited dissolved oxygen (= 10 ppm) which gets it further depleted. When the level of dissolved oxygen falls below 6 ppm, the fish cannot survive. Hence, they die and float dead in water.

Question 19.
How can domestic waste he used as manure?
Solution.
Manure: Domestic waste comprises of two types of materials, biodegradable such as leaves, rotten food, etc., and non-biodegradable such as plastics, glass, metal scrap, etc. The non-biodegradable waste is sent to industry for recycling. The biodegradable waste should be deposited in the land fills. With the passage of time, it is converted into compost manure.

Question 20.
For your agricultural field or garden, you have developed a compost producing pit. Discuss the process in the light of bad odour, flies and recycling of wastes for a good produce.
Solution.
The compost producing pit should be set up at a suitable place or in a tin to protect ourselves from bad odour and flies. It should be kept covered so that flies cannot make entry into it and the bad odour is minimized. The recyclable material like plastics, glass, newspapers, etc., should be sold to the vendor who further sells it to the dealer. The dealer further supplies it to the industry involved in recycling process.

MP Board Class 11 Chemistry Environmental Chemistry Important Questions and Answers

Question 1.
Name the region of atmosphere which contains ozone layer?
Answer:
Stratosphere.

Question 2.
How do pollutant and contaminant differ?
Answer:
Pollutant is a substance already present in atmosphere which spoils the environment by increase of its concentration due to human activities.
Contaminant is a substance that does not occur in nature but is introduced insignificant amount into the atmosphere by human action or accidentally.

Question 3.
Name the sink for carbon dioxide in atmosphere.
Answer:
Ocean and green plants.

Question 4.
What is the composition of London type Smog? Give its other name.
Answer:
Fog of H₂SO₄ droplets deposited on particulates.

Question 5.
Name the gases responsible for greenhouse effect.
Answer:
CO₂, CFC, Oxides of nitrogen, water vapours.

Question 6.
What is eutrophication?
Answer:
Eutrophication is the process of nutrient enrichment of water bodies and subsequent loss of biodiversity.

Question 7.
What the abbreviations FGD and BOD mean?
Answer:
FGD means Flue Gas Desulphurisation and BOD means Biochemical Oxygen Demand.

Question 8.
What does CFC stand for?
Answer:
Chlorofluorocarbons or freons.

Question 9.
What is PAN?
Answer:
Peroxyacyl nitrate, a toxic substance.

Question 10.
Name the chemicals responsible for acid rain.
Answer:
Oxides of sulphur, oxides of nitrogen.

Question 11.
Which part of the earth is given the name hydrosphere?
Answer:
Part of the earth comprising oceans, glaciers, polar caps, groundwater, etc.

Question 12.
Name different components of environment.
Answer:
Atmosphere, Hydrosphere, Lithosphere, Biosphere.

Question 13.
Name the various components into which atmosphere can be divided.
Answer:
Troposphere, Stratosphere, Mesosphere, Thermosphere.

Question 14.
Name various tropospheric pollutants.
Answer:
Oxides of sulphur, oxides of nitrogen are gaseous pollutants while dust and smoke are particulates.

Question 15.
How does CO₂ cause environmental pollution?
Answer:
CO₂ is non-toxic, yet it plays a significant role in global warming.

Question 16.
Which of the two is more toxic and why? CO₂ and CO.
Answer:
CO is more toxic because it binds itself to haemoglobin of blood to form carboxyhaemoglobin and blood loses its capacity to transport oxygen to lungs.

Question 17.
Explain the terms:
(a) Sink
(b) Receptor
Answer:
(a) Sink. The elements or organisms which consume a pollutant are known as sink. e.g. the micro-organisms act as sink for CO.
(b) Receptor. Organisms which are affected by pollutants are called receptors.

Question 18.
Briefly describe the height and temperature variation in various layers of atmosphere.
Answer:
Troposphere. The temperature decreases steadily with increase in altitude. The temperature near earth’s surface is about 210 K. This layer extends upto about 12 km from the surface of earth. The fall in temperature is due to fall in pressure and density of air.
Stratosphere.

It extends up to 50 km above the earth’s surface. It is characterised by increase in temperature with increase in altitude. The rise in temperature in this region is due to absorption of ultraviolet radiation of sun by ozone present in this region. Mesosphere. It extends from 50 km to 85 km in altitude. It is again characterised by rapid decrease in temperature to about 160 K. Thermosphere. This region is characterised by continuous rise in temperature.