Question

Describe simple experiments to show the presence of -

water vapour in air using a glass tumbler and ice.

Answer 1

Water vapour in air:

Apparatus- A clean dry beaker ,cube of ice

Procedure-

1. Take a clean glass beaker dried from outside and place pieces of ice in it.
2. Keep the beaker with the ice, aside for sometime.

Observation-

1. Tiny droplets of water appear on the outer surface of the beaker, which can be proved by using a dry blue cobalt chloride paper. It turns pink in the presence of water.

Conclusion-

1. The constituent of air-water vapour-  condenses on the cooler surface of the beaker, proving that air contains water vapour.