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Account for the following : (a) The te...

Account for the following :
(a) The temperature of water remains constant during boiling.
(b) Evaporation is a surface phenomenon.
(c ) The spaces between constituent particles is maximum in the gaseous state.

Text Solution

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(a) Once a liquid starts boiling, there is no increase in average kinetic energy upon further heating. The heat now supplied is used to overcome intermolecular forces only. Therefore, the temperature of water remains constant during boiling.
(b) Molecules or particles of a liquid present on the surface have an urge or desire to escape from the surface as vapours in order to increase their free movement or randomness. This is known as evaporation. Thus, evaporation is a surface phenomenon. More the surface area available more will be the rate of evaporation.
(c ) In the gaseous state of matter the interparticle forces are the least. Therefore, interparticle spaces are the maximum.
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