Test for Water Vapour in Air

Q. Air contains nitrogen and oxygen in 4:1 ratio of volumes. Prove it with an experiment. Also make a diagram depicting the same. [5 MARKS]

Q. If you take ice cold water in a glass tumbler, you will observe some water droplets on its outer surface. What can we infer from this?

1. Air occupies space.
2. Air contains nitrogen gas.
3. Air contains water vapour.
4. Air contains oxygen gas.

Q. Give reasons: [3 MARKS]
a) Clothes do not dry quickly on a cloudy day.
b) It is not advisable to fill hydrogen gas in big air balloons.
c) Balloons filled with helium gas float up into the air.