Air Around Us(6th Grade > Chemistry ) Questions and answers for exam Preparation

6th Grade > Chemistry

AIR AROUND US MCQs

Total Questions : 100 | Page 7 of 10 pages

Question 61.

Air is not present in:

Buildings
Ocean
Vacuum
Caves

Discuss Question

Answer: Option C. -> Vacuum
:
C

A vacuum is a space where there is no matter. Even, the air is not present in it. Therefore, the air is present everywhere except in a vacuum.

Question 62.

Statement I: Mountaineers carry oxygen cylinders with them while climbing high mountains.

Statement II: The percentage of oxygen in air decrease with increasing altitude.

Statement I is true and statement II is the correct explanation
Both statements are false
Statement I is true and statement II is false
Statement I is false and statement II is true

Discuss Question

Answer: Option C. -> Statement I is true and statement II is false
:
C

The percentage of oxygen in air is the same at sea level as it is at high altitudes, which is around 21%. However, at high altitudes the pressure is lower and air is more spread out leading to less oxygen availbility for our body. Hence, mountaineers carry oxygen cylinders with them while climbing high mountains.

Question 63.

The gas present in the atmosphere which is essential for respiration is:

Oxygen
Carbon dioxide
Nitrogen
Hydrogen

Discuss Question

Answer: Option A. -> Oxygen
:
A

The gas present in the atmosphere which is essential for respiration is oxygen. Oxygen constitutes about 21% of the Earth's atmosphere.

Question 64.

Statement I: Policemen regulating traffic at a crowded crossing often wear a mask.
Statement II: Mask filters carbon dioxide and sends pure oxygen inside.

Both statements are true
Both statements are false
Statement I is true and statement II is false
Statement I is false and statement II is true.

Discuss Question

Answer: Option C. -> Statement I is true and statement II is false
:
C

The air at a crowded crossing is generally very polluted. The mask over policemen's nose filters dust from the air but it is not meant to filter carbon dioxide.

Question 65.

The component of air used by green plants to make their food is:

Sulphur dioxide
Nitrogen
Oxygen
Carbon dioxide

Discuss Question

Answer: Option D. -> Carbon dioxide
:
D

Plants need carbon dioxide for photosynthesis through which they produce food for themselves. During photosynthesis, plants take in sunlight, water and carbon dioxide to produce starch and release oxygen as a byproduct.

Question 66.

The most abundant constituent of air is _____.

oxygen
nitrogen
water vapour
impurities

Discuss Question

Answer: Option B. -> nitrogen
:
B

The most abundant constituents of air is Nitrogen. The constituents of air are:

Water vapour is also an important constituent which varies from region to region.

Question 67.

Air doesn't support burning.

True
False
Statement I is true and statement II is false
Statement I is false and statement II is true

Discuss Question

Answer: Option B. -> False
:
B

Air consists of oxygen which assists burning. Oxygen is necessary for burning of everything.

Question 68.

A lump of cotton shrinks in water because:

Air present in lump of cotton is replaced by water which occupies less space.
There are tiny spaces occupied by air in cotton lump. When placed in water, these spaces get closed.
Water cleans the cotton lump, making it shrink in size.
Water pushes the cotton lump from all directions, making it shrink in size.

Discuss Question

Answer: Option A. -> Air present in lump of cotton is replaced by water which occupies less space.
:
A
A lump of cotton is porous, it has air in it. When it is dipped in water, water removes air and occupies the space. Space occupied by water is less than that occupied by air.

Question 69.

Statement I: When water is heated, we see bubbles in it.

Statement II: The bubbles are due to air present inside the water.

Statement I is true and statement II is the correct explanation.
Statement I is true and statement II is not the correct explanation.
Statement I is rrue and statement II is false.
Statement I is false and statement II is true.

Discuss Question

Answer: Option A. -> Statement I is true and statement II is the correct explanation.
:
A

When water is heated, bubbles are seen due to the presence of air inside water. On heating, air tries to escape out of the water and so bubbles are seen.

Question 70.

Which of the following gas is used to fill the packets of potato chips?

Oxygen
Carbon dioxide
Hydrogen
Nitrogen

Discuss Question

Answer: Option D. -> Nitrogen
:
D
Nitrogen is used to fill the packets of potato chips because unlike many other gases, nitrogen doesn't react with the food present in the packet. Hence, the flavour of the food doesn't change and remains edible for longer time.