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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
Evaporation is rapid on a wet day.
Evaporation takes place only from the surface of liquid.
All molecules of a liquid take part in the process of evaporation.
The molecules of liquid ............. heat from surroundings in evaporation.
Cooling is produced in ....................
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 |
In evaporation
Comment on the statement ‘evaporation is a surface phenomenon’.
Why is cooling produced when a liquid evaporates?
How is the heat energy supplied to a liquid used during boiling at a fixed temperature?
