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प्रश्न
What is boiling? Explain it on the basis of molecular motion?
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उत्तर
BOILING: “The change of liquid to vapours on heating at a constant temperature is called BOILING”
K.E = `1/2`Mv2: more the speed of molecules more is the kinetic energy. Heating of the liquid increases the average kinetic energy of liquid molecules and molecules acquire sufficient K.E. needed to overcome the force of attraction of other molecules. These molecules start leaving the liquid not only at the surface but also near the walls of the containing vessel and bubbles are seen on the walls of the vessel. This causes the agitation in the whole of the liquid and this is called boiling.
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संबंधित प्रश्न
Temperature of a liquid rises during boiling or vaporization
Boiling is a rapid phenomenon.
Boiling occurs at ....................
Evaporation takes place at ................. .
Heat is ................... during boiling.
Match the column
| Column A | Column B |
| (a) Blowing air increases | (1) Increase in intermolecular separation |
| (b) Increase in pressure increases | (2) Pendulum of a clock |
| (c) Thermal expansion |
(3) Cooking utensils |
| (d) Invar | (4) Boiling point |
| (e) Pyrex glass | (5) Evaporation |
Comment on the statement ‘evaporation is a surface phenomenon’.
Give reason for the increase in rate of evaporation of a liquid when air is blown above the liquid.
Give reason for the increase in rate of evaporation of a liquid when surface area of liquid is increased.
What is the change in average kinetic energy of molecules of a liquid during boiling at its boiling point?
