Question

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.


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Answer 1

Answer:

Naphthalene undergoes sublimation easily i.e., the change of state of naphthalene from solid to gas without the intervention of the liquid state. Thus, naphthalene balls keep on forming naphthalene vapours which disappear into the air with time without leaving any solid. 2 When perfume is released it quickly changes into vapour. The kinetic energy of gas molecules is high & the rate of diffusion is high. Hence we can smell the perfume sitting several metres away.

Answer 2

(a) The sublimation occurs in naphthalene. The process of conversion of solid state of matter in to gaseous state of matter without reaching the liquid state is called sublimation. Naphthalene disappears into vapors hence Naphthalene balls disappear with time without leaving any solid

(b)When perfume is released it quickly changes into vapour. The kinetic energy of gas molecules is high & the rate of diffusion is high. Hence we can smell the perfume sitting several metres away.

hope it helps:)