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Give reason for the following observatio...

Give reason for the following observations.
(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.

Text Solution

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(a) Naphthalene has a tendency to sublime i.e. it changes directly to the gaseous state. Therefore, the size of the naphthalene balls slowly decreases and ultimately they disappear. No solid residue is left.
(b) A perfume is actually a mixture of number of pleasant smelling vapours. They diffuse quite fast and can reach a person who may be even at several metres away from a person who has used perfume.
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