Constituents of Air

Q.

With the help of an experiment prove that exhaled air contains carbon dioxide.

Q.

The hissing sound that is heard when water is poured over quicklime is due to the evolution of:

1. ${\mathrm{H}}_2$ gas

2. ${\mathrm{O}}_2$ gas

3. ${\mathrm{CO}}_2$ gas

4. Steam

Q. The main constituent in air is _______.

1. oxygen
2. nitrogen
3. carbon dioxide
4. sulphur dioxide

Q. The second most abundant gas in the atmosphere is carbon dioxide.

1. True
2. False

Q. Hydrogen gas is collected by the downward displacement of water.

1. True
2. False

Q.

Which of the following statement explains why oxygen can be separated from nitrogen by the fractional distillation of liquid air?

1. Oxygen is denser than nitrogen

2. Oxygen is more reactive than nitrogen

3. Both oxygen and nitrogen have different boiling points

4. Both oxygen and nitrogen are in different groups in the Periodic Table

Q.

Short answer questions
How will you test the presence of carbon dioxide in exhaled air?

Q.

How can you observe the three forms of water in (i) nature and (ii) at home?

Q.

Statement 1- Air is a mixture.

Statement 2- Composition of air is fixed

1. Statement 1 is True and statement 2 is False
2. Statement 1 is True and Statement 2 is True
3. Statement 1 is False and statement 2 is False
4. Statement 1 is False and statement 2 is True

Q. Choose the correct statement:

1. Hydrogen gas is collected by downward displacement of water.
2. Hydrogen gas is collected by downward displacement of air.
3. Hydrogen gas is collected by upward displacement of air.
4. Hydrogen gas is collected by upward displacement of water.

Q.

An experiment was performed to know about the source of air for the aquatic organisms. The experiment was as follows:

Take some water in a glass vessel. Heat it slowly on a tripod stand. Before the water begins to boil, look carefully at the inner surface of the vessel. Observe the bubbles that are coming up. Where are these bubbles coming from?

1. The bubbles are water bubbles

2. The bubbles come from the air dissolved in water

3. The liquid in the beaker is not water

4. The bubbles are formed due to glass vessel

Q.

Most of the gases can be seen with the naked eye.

1. True
2. False

Q.

Write any three applications of oxygen.

Q.

Which of the following supports combustion?

1. Carbon dioxide

2. Nitrogen

3. Oxygen

4. Argon

Q. _______ of air is used to obtain nitrogen, oxygen, and argon and other atmospheric noble gases by separating the air components by fractional distillation in a cryogenic air separation unit.

1. Liquefaction
2. Chromatography
3. Diffusion
4. All of above

Q.

In which forms, water exists on the Earth?

Q.

Define air.

Q.

Air is necessary for burning any fuel.

1. True
2. False

Q.

What is the most common method of air separation?

1. Cryogenic distillation

2. Gas chromatography

3. Centrifuge

4. Fractional distillation

Q. <!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> Discuss the composition of air.

Q.

90 Out of all gases present in the air, name those which do not support burning?

Q. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Mention two man-made and two natural sources of air pollution.

Q.

Air is a mixture of

1. Oxygen and nitrogen

2. Carbon dioxide and oxygen

3. Various gases, dust particles and water vapour.

4. Oxygen and dust particles

Q.

Circle the odd one out. Give reasons for your choice.

1. Methane

2. Water vapour

3. Carbon dioxide

4. Nitrogen

Q. Inactive component of air constitutes approximately ______ the volume of air.

1. $\frac{1}{5}$
2. $\frac{2}{5}$
3. $\frac{3}{5}$
4. $\frac{4}{5}$

Q.

Give two examples for each of the following:

Chemical formula

Q.

The second most abundant constituent of air is

1. Oxygen

2. Nitrogen

3. Water vapour

4. Impurities

Q. Inactive component of air ____ combustion.

1. supports
2. does not support
3. none of the above
4. depends on air

Q. The inactive component of air is:

1. oxygen
2. nitrogen
3. both A and B
4. none of the above

Q. Phosphorous pentoxide dissolves in water to form:

1. phosphorous acid
2. phosphoric acid
3. phosphorous pentoxide
4. phosphorous oxide