DAV Class 8 Science Chapter 19 Solutions Pollution of Air of The Living World Science Book guides you with the answers to the questions given in the textbook. Class 8 is an important phase of the student’s life as they are introduced to many new concepts that are essential to set strong basics foundation for the topics to be taught in Class 9.
While solving chapter 19 Pollution of Air of Science textbook, students often face several doubts and eventually get confused. To help DAV Class 8 students clear all their doubts instantly, Class 8 Science Chapter 19 question answer Pollution of Air come as a great resource. Here, the detailed Solutions for Class 8 Science Chapter 19 of Science book are given below.
DAV Class 8 Science Chapter 19 Pollution of Air Solutions
DAV Class 8 Science chapter 19 question answer Pollution of Air, is given below. Here DAV Class 8 Science Chapter 19 solutions is provided with great explanation.
- Fill in the blanks
- State True or False
- Tick the correct option
- Answer the following questions in brief
- Answer the following questions
These DAV Class 8 Science Chapter 19 Pollution of Air Solutions will help you in scoring good marks as they cover important concepts in different patterns like fill in the blanks, tick the correct option, State True or False for the following statements, Answer the following questions in brief and Answer the following questions.
DAV Class 8 Science Chapter 19 Solutions
A. Fill in the blanks.
1. ___________ and ___________ gases dissolve in water to form acid rain.
2. The phenomena of corrosion of marbles of the monument, by acid rain, is called ___________.
3. ___________ and ___________ are two of the main greenhouse gases.
4. The phenomenon, of likely increase in earth’s average temperature (due to increase in the amount of greenhouse gases), is known as ___________.
Answer: (1) Nitrogen dioxide, sulphur dioxide (2) marble cancer (3) carbon dioxide, methane (4) global warming.
B. State True or False for the following statements.
1. Burning of fossil fuels is one of the many causes of air pollution.
2. High concentration of nitrogen dioxide, in the atmosphere, can result in respiratory problems.
3. The ultraviolet rays of the sun get absorbed mainly by the oxygen present in the atmosphere.
4. Acid rain does not corrode metals.
5. Sulphur dioxide is one of the ‘greenhouse gases’.
Answer: (1) True (2) True (3) False (4) False (5) False.
C. Tick the correct option.
1. Which of the following is responsible for depletion of ozone layer?
2. An increase, in the amount of carbon dioxide and methane in the atmosphere, is likely to lead to-
Answer: global warming.
3. The main gases, that trap the solar heat radiations after their reflection from the earth, are-
Answer: carbon dioxide, methane, water vapours.
4. Taj Mahal, at Agra, may get damaged if its surrounding atmosphere contains more of-
Answer: sulphur dioxide.
5. Smoke combines with water vapours and dust particles, in the presence of sunlight, to form-
D. Answer the following questions in brief.
1. Define the term ‘pollutant’.
Answer: a substance capable of causing harmful effects, when present in the environment in proportions greater than its natural abundance.
2. State two causes of air pollution.
Answer: two causes of air pollution are:
- Excessive burning of fossil fuels, like coal, kerosene, petrol or diesel.
- Smoke, from factories and vehicles.
3. How is carboxy haemoglobin formed?
Answer: Carbon monoxide, when inhaled, passes through the lungs into the blood. It combines with the haemoglobin to form a complex substance known as carboxy haemoglobin.
4. State the harmful effects of chlorofluorocarbons.
Answer: CFCs cause the depletion of ozone layer by decomposing ozone to oxygen.
5. Suggest any three measures that can help to check global warming.
Answer: three measures that can help to check global warming are:
- Deforestation must be stopped.
- More trees should be planted.
- Use of chlorofluorocarbons must be reduced.
E. Answer the following questions.
1. Give the meaning of the term ‘smog’. List its harmful effects.
Answer: In winters, a thick fog-like layer envelops the atmosphere. This layer is made up of smoke and fog. When smoke, containing oxides of nitrogen, combines with other air pollutants and fog, it forms smog.
Harmful effects of smog
- It leads to diseases related to lungs (such as bronchitis, asthma, etc.).
- It prevents the sunlight from reaching the earth; this affects the normal functioning of plants.
2. Write a short note on ‘acid rain’.
Answer: Excessive carbon dioxide, smoke and nitrogen dioxide, when released in the atmosphere, come in contact with the water vapours present there. This results in the formation of sulphuric acid and nitric acid. These acids then fall down with rain, making it acidic; such rain is called acid rain.
3. List the main causes of increase in concentration of greenhouse gases in the atmosphere.
Answer: the main causes of increase in concentration of greenhouse gases in the atmosphere are:
- Coal and wood, when burnt as domestic fuels, release carbon dioxide gas into the atmosphere.
- Thermal power plants use the heat produced, through burning of coal, to generate electricity. This leads to enormous release of carbon dioxide and carbon monoxide gases into the atmosphere.
- Indiscriminate deforestation causes imbalance in the concentration of carbon dioxide in the atmosphere.
4. State the likely consequences of an increase in the ‘greenhouse effect’.
Answer: the likely consequences of an increase in the ‘greenhouse effect’ are:
- Due to greenhouse effect, the average temperature of the earth’s atmosphere is gradually increasing. This is called global warming.
- Warming of atmosphere often leads to forest fires; these have become more common over the years.
- Glaciers will melt at a higher rate and this will lead to a rise in the sea level resulting in floods and loss of soil.
5. Write any five methods that can help to control air pollution.
Answer: Five methods that can help to control air pollution are:
- Use of CNG in automobiles.
- Plant more trees (afforestation).
- Enforce strict anti-pollution measures.
- Avoid the burning of dry vegetable wastes.
- Use of smokeless chulhas, solar cookers and biogas for cooking purposes.