Properties of Air and Water NDA Questions

NDA Chemistry

Properties of Air and Water MCQ Questions


13.
The invisible water present in air in the form of vapour is known as:
A.
Precipitation
B.
Condensation
C.
Humidity
D.
Sublimation
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ANSWER :
C. Humidity
14.
Which gas present in the air is essential for supporting combustion (burning)?
A.
Oxygen
B.
Water vapour
C.
Nitrogen
D.
Carbon dioxide
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ANSWER :
A. Oxygen
15.
When a burning candle is covered with an inverted glass jar, it eventually gets extinguished. This happens because:
A.
The oxygen inside the jar gets used up during burning
B.
The nitrogen inside the jar is used up
C.
The candle runs out of wax immediately
D.
The jar becomes too hot
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ANSWER :
A. The oxygen inside the jar gets used up during burning
16.
Which simple test is used to detect the presence of carbon dioxide gas, such as in the air we exhale?
A.
It has a strong smell of rotten eggs
B.
It turns blue litmus red
C.
It turns red litmus blue
D.
It turns freshly prepared lime water milky
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ANSWER :
D. It turns freshly prepared lime water milky
17.
When we breathe out through a straw into a test tube containing lime water, the lime water turns milky. This confirms that exhaled air contains a higher proportion of:
A.
Carbon dioxide
B.
Nitrogen
C.
Argon
D.
Oxygen
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ANSWER :
A. Carbon dioxide
18.
If a burning matchstick is brought near a gas jar filled with pure oxygen, the flame will:
A.
Get extinguished immediately
B.
Burn more vigorously and brightly
C.
Turn blue in colour
D.
Produce no visible change
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ANSWER :
B. Burn more vigorously and brightly