Question

give reason for the following observation. (a) napathalene balls disappear with time without leaving any solid (b) we can get the smell of perfume sitting several meters away.​

Answer 1

Explanation:

Napthlene balls are sublimable solids i.e. they get converted from solids to gases directly without passing through the liquid state. Hence, napthelene balls dissappeae with time without leaving any solid.

When a perfume is sprayed, its molecules mix with air. Hence, we can get the smell of perfume sitting meters away.

Answer 2

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(a) At room temperature, naphthalene balls undergo sublimation wherein they directly get converted from a solid to a gaseous state without having to undergo the intermediate state, i.e., the liquid state.

(b) Molecules of air move at a higher speed and have large intermolecular spaces. Perfumes comprise of flavoured substances that are volatile which scatters quickly in air, becoming less concentrated over a distance. Hence we are able to smell perfume sitting several metres away.

Hope it Helps !!