Exercise III on Air Atmosphere Class 6 Concise Chemistry ICSE Solutions Ch-6. In this article you would learn how to solve Exercise III on Air Atmosphere with hint and reason. Visit official Website CISCE for detail information about ICSE Board Class-6.
Exercise III on Air Atmosphere
| Board | ICSE |
| Publications | Selina Publication |
| Subject | Chemistry |
| Class | 6th |
| Chapter-6 | Air Atmosphere |
| Book Name | Concise |
| Topics | Solution of Exercise III |
| Academic Session | 2025-2026 |
Exercise III on Air Atmosphere
Objective Type Questions
Que-1: Air pollution is caused due to :
(i) cutting of green plants
(ii) smoke given out by factories
(iii) gases like carbon monoxide, sulphur dioxide, etc.
(iv) all of the above.
Ans- all of the above
Reason — Air pollution is the presence of harmful substances in the air that can affect human health, animals, plants, and the environment. It is caused by cutting green plants, smoke given out by factories and harmful gases like carbon monoxide and sulphur dioxide.
Que-2: The gases which cause acid rain are:
(i) sulphur dioxide and oxygen
(ii) nitrogen and oxygen
(iii) carbon dioxide and water vapour
(iv) nitrogen dioxide and sulphur dioxide.
Ans- nitrogen dioxide and sulphur dioxide
Reason — Gases like sulphur dioxide and nitrogen dioxide (pollutant) get mixed in rain water to form acid rain.
Que-3: Which of the following is not a greenhouse gas?
(i) Carbon dioxide
(ii) Sulphur dioxide
(iii) Methane
(iv) Nitrous oxide
Ans- Sulphur dioxide
Reason — Green house gases are carbon dioxide, methane, nitrous oxide, which traps more heat from the sunlight. In contrast, sulphur dioxide is not a green house gas.
Que-4: Common air pollutants that cause respiratory diseases are:
(i) ozone
(ii) inert gases
(iii) dust and smoke
(iv) water vapour
Ans- dust and smoke
Reason — Common air pollutants like dust and smoke cause respiratory, skin and eye problems.
Que-5: The gas responsible for ozone depletion is:
(i) oxygen
(ii) chlorofluorocarbons
(iii) carbon dioxide
(iv) sulphur dioxide
Ans- chlorofluorocarbons
Reason — Air pollutants like chlorofluorocarbons (CFCs) reacts with the ozone in the atmosphere and reduce the density of ozone in the stratosphere.
Fill in the Blanks
Que-1: The layer of air around the earth is called the .. …. ….. .
Ans- The layer of air around the earth is called the atmosphere.
Que-2: Although we cannot see air, we can …. … …. it.
Ans- Although we cannot see air, we can feel it.
Que-3: Air is a … …. …. of gases.
Ans- Air is a mixture of gases.
Que-4: Plants and animals maintain the balance of …. …. … and … …. …. in air.
Ans- Plants and animals maintain the balance of oxygen and carbon dioxide in air.
Que-5: Polluted air is …. … …. for health.
Ans- Polluted air is harmful for health.
Que-6: The supporter of combustion in air is …. … …. .
Ans- The supporter of combustion in air is oxygen.
Que-7: Green plants need .. ….. …. to prepare food.
Ans- Green plants need carbon dioxide to prepare food.
Que-8: Oxygen is used in …. … …. of the food to get …. .. ….. .
Ans- Oxygen is used in digestion of the food to get energy.
Que-9: Aquatic plants and animals use … ….. … in water.
Ans- Aquatic plants and animals use dissolved oxygen in water.
Que-10: The reddish brown powder on the surface of iron nails exposed to air and moisture is called … …… .. .
Ans- The reddish brown powder on the surface of iron nails exposed to air and moisture is called rust.
State True or False
Write ‘true’ or ‘false’ for the following:
Que-1: Air is a compound. …. …. …
Ans- False
Correct Statement — Air is a mixture.
Que-2: Carbon dioxide is given out during photosynthesis. ….. … …
Ans- False
Correct Statement — During photosynthesis, oxygen is released and carbon dioxide is absorbed by plants to make food.
Que-3: Respiration needs nitrogen. ….. … …
Ans- False
Correct Statement — Respiration needs oxygen.
Que-4: The composition of air was discovered by Lavoisier. …. …. …
Ans- True
Que-5: The major component of air is oxygen. .. …. …..
Ans- False
Correct Statement — The major component of air is nitrogen (78 %).
Match the Following
Ans- (a) – (ii)
(b) – (iv)
(c) – (v)
(d) – (iii)
(e) – (i)
Short Answer Questions
Que-1: What is air pollution ?
Ans- Air pollution is the contamination of air by harmful substances such as smoke, dust, poisonous gases, and other pollutants, making it harmful to living organisms and the environment.
Que-2: Name two air pollutants which
(i) affect our health,
(ii) cause acid rain,
(iii) cause global warming.
Ans- (i) Air pollutants which affect our health:
(a)Smoke
(b)Carbon monoxide
(ii) Air pollutants which cause acid rain:
(a)Sulphur dioxide (SO₂)
(b)Nitrogen dioxide (NO₂)
(iii) Air pollutants which cause global warming:
(a)Carbon dioxide (CO₂)
(b)Methane (CH₄)
Que-3: Name three greenhouse gases.
Ans- Three greenhouse gases are:
(i) Carbon dioxide (CO₂)
(ii) Methane (CH₄)
(iii) Water vapour (H₂O)
Long Answer Type Questions
Que-1: What is meant by ozone depletion?
Ans- Ozone depletion is the gradual thinning or reduction in the amount of the ozone layer present in the upper atmosphere (stratosphere). The ozone layer contains ozone gas (O₃), which acts as a protective shield by absorbing most of the harmful ultraviolet (UV) rays coming from the Sun.
The main cause of ozone depletion is the release of chemicals such as chlorofluorocarbons (CFCs), halons, and other ozone-depleting substances from refrigerators, air conditioners, aerosol sprays, and industrial processes. When these chemicals reach the stratosphere, they break down under sunlight and release chlorine and bromine atoms. These atoms react with ozone molecules and destroy them.
Que-2: Mention five causes of air pollution.
Ans- Five Causes of Air Pollution
(i)Burning of fossil fuels such as coal, petrol, and diesel in vehicles, industries, and power plants.
(ii)Industrial emissions that release harmful gases and smoke into the atmosphere.
(iii)Burning of garbage, wood, and crop residues, which produces smoke and toxic gases.
(iv)Deforestation, which reduces the number of trees available to absorb carbon dioxide and other pollutants.
(v)Dust and particulate matter from construction activities, mining, and roads that contaminate the air.
Que-3: State four steps to be taken to control air pollution.
Ans- Air pollution can be controlled by taking the following steps:
(i)Plant more trees: Trees absorb carbon dioxide and other harmful gases from the air and release oxygen. They help keep the air clean and fresh.
(ii)Use public transport and cleaner fuels: Using buses, trains, carpooling, or cleaner fuels reduces the number of vehicles on the roads and decreases air pollution.
(iii)Avoid burning garbage and crop waste: Burning waste produces smoke and harmful gases. Proper disposal and recycling of waste help reduce air pollution.
(iv)Control industrial emissions: Factories should install filters and other pollution-control devices in their chimneys to prevent harmful gases and dust from entering the atmosphere.
Que-4: Study the diagram and name the processes A, B and C.
Ans- (i) A is Respiration — Respiration is a chemical process that takes place in all living beings. In this process, oxygen that we breathe in with air reacts with the digested food in our body. This results in the release of energy, carbon dioxide and water.
(ii) B is Photosynthesis — Photosynthesis is a process in which carbon dioxide is used by green plants to prepare their food. Oxygen is released during this process which is then used for respiration by both plants and animals.
(iii) C is Burning of fuels — Burning (Combustion) is a process in which a substance reacts chemically with oxygen and gets oxidised, with the release of energy in the form of heat and light.
Que-5: In an experiment done with a burning candle, the apparatus was set up as shown below. Initially, the candle burns but after sometime it gets extinguished.
Look at the diagram and answer the questions given below.
(i) Label A and B.
(ii) Why does the candle burn in (I) but gets extinguished in (II) ?
(iii) Why does the water level rise after sometime ?
(iv) What conclusion is drawn by the experiment show above ?
Ans- (i) In the given diagram A and B are:
A → Air
B → Inactive air
(ii) The candle burn in (I) because of the presence of ‘active air’ that contains oxygen, which is used by the candle to burn. The candle does not burn in case of (II), because the jar consist of ‘inactive air’, consist mainly nitrogen, which does not support burning.
(iii) When the candle is lit in the jar, it starts burning using the active air present in the jar, upto one-fifth part of the jar containing oxygen helps the candle to burn. After sometime the candle gets extinguished and the water level rises upto one-fifth part of the jar to compensate the loss of oxygen.
(iv) This proves that air contains both oxygen and nitrogen. It clearly explains that air is made up of an ‘active’ part and an ‘inactive’ part. The ‘active’ part of air, which is used up when substances burn, is about one-fifth of the total volume of the air. It is a gas called oxygen. The ‘inactive’ part, which does not support burning, consists mainly of a gas called nitrogen, constituting 4/5th of air by volume.
Case Study Type Questions
Que-1: Riya was travelling with her parents in a big city. She noticed that the sky looked hazy and the buildings far away were not clearly visible. Her mother explained that this happens because harmful gases and tiny particles like smoke, soot and dust get mixed with the air. These come mainly from vehicles, burning of fuels and factories. Breathing such polluted air can make people sick and also harm animals and plants.
(i) Define air pollution?
(ii) Why is the air in big cities often less clear than in small towns or villages?
(iii) Mention two common health problems that people may suffer from due to air pollution.
(vi) Suggest two ways in which we can reduce harmful substances mixing in the air.
(v) How are solar energy and electrical energy better than using fossil fuels?
Ans- (i) Air pollution is the mixing of harmful substances in the air that make the air unsafe for living beings.
(ii) The air in big cities is often less clear because there are more vehicles, industries, and burning of fuels. These release large amounts of smoke, soot, and harmful gases into the air, making it hazy compared to cleaner air in villages.
(iii) Two common health problems caused by air pollution are coughing and eye irritation.
(vi) Two ways in which we can reduce harmful substances mixing in the air:
(i) Growing more trees and plants. Trees clean the environment and also help in bringing more rains which make the atmosphere free from pollutants.
(ii) Industries should be located far away from residential areas.
(v) Solar energy and electrical energy are better than fossil fuels because they do not produce smoke or harmful gases. They are clean, renewable, and help reduce air pollution and protect the environment.
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