Question

give reasons for the following observations
a) naphthalene balls disappear with time without leaving any solid.
b) we can get the smell of perfumes sitting several metres away.​

Answer 1

Answer:

1. naphthalene have the property of sublimation that is a solid directly converts into gas without leaving any remains of solid.
2. it is due to the fact that particles of perfume spread in the air which makes the air move and it reaches to the nearby place..

Answer 2

Answer:

a) Naphthalene is a sublimatory substance. After some days, it changes from solid to gas i.e. sublimates without leaving any residue.

b) Perfume is a highly volatile substance. When it is applied it immediately evaporates and changes from liquid to gaseous state. Gases can diffuse to relatively longer distances because of their high intermolecular spaces. Hence we can get the mell of perfumes sitting several metres away.

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