Exercise I on Air Atmosphere Class 6 Concise Chemistry ICSE Solutions Ch-6. In this article you would learn how to solve Exercise I on Air Atmosphere with hint and reason. Visit official Website CISCE for detail information about ICSE Board Class-6.
Exercise I on Air Atmosphere
| Board | ICSE |
| Publications | Selina Publication |
| Subject | Chemistry |
| Class | 6th |
| Chapter-6 | Air Atmosphere |
| Book Name | Concise |
| Topics | Solution of Exercise I |
| Academic Session | 2025-2026 |
Exercise I on Air Atmosphere
Objective Type Questions
Que-1: Air consists of:
(i) only oxygen
(ii) only nitrogen
(iii) only carbon dioxide
(iv) all of these.
Ans- all of these.
Reason — The main gases present in air are nitrogen and oxygen. Besides these two gases, air also contains small quantities of carbon dioxide, water vapour, dust particles, smoke and traces of inert gases like helium, neon, argon, etc.
Que-2: The most abundant gas in Earth’s atmosphere is:
(i) oxygen
(ii) nitrogen
(iii) carbon dioxide
(iv) argon
Ans- nitrogen
Reason — The most abundant gas in Earth’s atmosphere is Nitrogen. The amount of nitrogen in air is 78%.
Que-3: Which of the following gases supports burning?
(i) oxygen
(ii) nitrogen
(iii) carbon dioxide
(iv) water vapour
Ans- oxygen
Reason — The ‘active part’ of air, which is used up when substances burn, is called oxygen. It is present about one-fifth of the total volume of the air.
Que-4: Air is a mixture because:
(i) the components of air retain their individual properties.
(ii) energy change takes place when the components of air are mixed together.
(iii) the composition of air remains the same everywhere.
(iv) the components of air cannot be separated by simple physical methods.
Ans- the components of air retain their individual properties.
Reason — Air is a mixture because the components of air retain their individual properties. Other options are not true because no energy change takes place, the composition of air varies from place to place and the components of air can be separated by physical methods.
Que-5: Oxygen in air is:
(i) 4/5 parts
(ii) 1/5 parts
(iii) 1/3 parts
(iv) negligible
Ans- 1/5 parts
Reason — The ‘active part’ of air i.e., oxygen is present about one-fifth (1/5 parts) of the total volume of the air.
Name the Following
Write the chemical name of:
(i) Lime Water
(ii) The White insoluble solid formed on reaction of carbon dioxide with lime water.
Ans- (i) Calcium hydroxide
(ii) Calcium carbonate
Short Answer Questions
Que-1: What is atmosphere ?
Ans- Atmosphere is the envelope (blanket) of gases surrounding the Earth, held around it by gravity. It consists mainly of nitrogen (about 78%), oxygen (about 21%), and small amounts of other gases such as carbon dioxide, argon, and water vapour. The layer of gases surrounding the Earth is called the atmosphere.
Que-2: Why can’t we see air ?
Ans- We cannot see air because it is a colourless and transparent gas. Air allows light to pass through it without significantly reflecting or absorbing the light, so our eyes cannot detect it directly.
Que-3: What is wind?
Ans- Wind is moving air. The movement of air from one place to another is called wind.
Que-4: What would have happened if there would have been no atmosphere around the earth ?
Ans- If there were no atmosphere around the Earth:
(i) There would be no air (oxygen) for living organisms to breathe.
(ii) The Earth would experience extreme temperatures very hot during the day and very cold at night.
(iii) There would be no weather, such as wind, clouds, or rain.
(iv) Harmful radiation from the Sun would reach the Earth’s surface directly.
(v) Meteoroids would not burn up before reaching the Earth.
Que-5: What do you observe when
(i) Ice cold water is filled in a glass tumbler.
(ii) A burning candle is covered with an inverted jar.
(iii) Carbon dioxide gas is passed through lime water.
(iv) A beam of light is allowed to enter in a closed dark room through a small hole.
Ans- (i) Ice-cold water is filled in a glass tumbler.
Tiny droplets of water appear on the outer surface of the tumbler due to condensation of water vapour from the air.
(ii) A burning candle is covered with an inverted jar.
The candle burns for a short time and then goes out because the oxygen inside the jar gets used up.
(iii) Carbon dioxide gas is passed through lime water.
The lime water turns milky due to the formation of a white precipitate of calcium carbonate.
(iv) A beam of light is allowed to enter a closed dark room through a small hole.
The path of the light beam becomes visible because dust particles suspended in the air scatter the light.
Long Answer Type Questions
Que-1: Why is air called a mixture ? Give five facts in support of your answer.
Ans- Air is called a mixture because it consists of several gases and other substances physically mixed together, not chemically combined.
Five facts in support of this statement:
(i) Air is made up of different gases: Air contains mainly nitrogen, oxygen, carbon dioxide, water vapour, argon and other gases.
(ii) The constituents of air retain their individual properties: Oxygen in air supports burning, carbon dioxide turns lime water milky, and nitrogen remains largely inactive. Each gas behaves as it would when separate.
(iii) The composition of air is not fixed: The amount of water vapour, carbon dioxide and dust particles varies from place to place and from time to time.
(iv) The components of air can be separated by physical methods: The gases present in air can be separated by processes such as fractional distillation of liquid air.
(v) No new substance is formed when the gases mix: The gases in air are only mixed together physically; they do not chemically combine to form a new substance.
Que-2: What are the main components of air ? Write down the composition of the three main gases present in air by volume.
Ans- Air is a mixture of several gases along with water vapour, dust particles and smoke. It forms the atmosphere that surrounds the Earth and is essential for the survival of living organisms. The major constituents of air are nitrogen, oxygen and carbon dioxide. Besides these, air also contains small amounts of argon, neon, helium, krypton and water vapour.
The composition of the three main gases present in air by volume is as follows:
(i) Nitrogen (N₂) – about 78%
(ii) Oxygen (O₂) – about 21%
(iii) Carbon dioxide (CO₂) – about 0.03–0.04%
The remaining about 1% consists of argon, water vapour and other rare gases.
Importance of the main gases:
(i) Nitrogen is required by plants for the manufacture of proteins and helps in maintaining soil fertility.
(ii) Oxygen is essential for respiration in living organisms and supports combustion.
(iii) Carbon dioxide is used by green plants during photosynthesis to prepare food and release oxygen.
— : End of Exercise I on Air Atmosphere Class 6 Concise Chemistry ICSE Solutions :–
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