Question

Which one of the following statements related to the process of evaporation is incorrect?
A.Evaporation occurs at any temperature
B.Evaporation takes place within the liquid not on the surface
C.The temperature may change during evaporation
D.No bubbles are formed in the liquid during evaporation.

Answer 1

Evaporation is defined as the process of conversion of the liquid state of any compound into a gaseous state below its boiling point. It is an important part of the exchange of energy in the earth-atmosphere system.

Complete step by step answer:
For evaporation to occur, the energy of the molecules should be greater than the minimum energy required for the phase change to occur, and this energy is gained by the molecules when the temperature is higher. And this temperature for phase change is different for different substances. Hence the statement that evaporation occurs at any temperature is true since there is no particular temperature defined for evaporation. It is a process in which the molecules available on the surface of the liquid gain enough energy to overcome the surface tension and get into the gaseous phase and evaporate.
Hence, Option B that states that evaporation takes place within the liquid and not on the surface is incorrect.
As the molecules gain kinetic energy and with an increase in energy as they escape the liquid phase to the gaseous phase the average energy reduces and hence, there is a temperature change. Hence, the statement of option C is correct.
We don’t see the bubbles getting created at the time of evaporation as it is a surface phenomenon. So the statement for option D is correct.
Hence the correct answer is option B.

Note:
Evaporation can happen in the case of solid also of the solid is sublime and for the liquids having higher vapour pressure or lower surface tension, evaporation proceeds more quickly. Also, Sweat that evaporates from the Human body provides a cooling effect as when the fast-moving electrons escape, the overall energy reduces, and hence the temperature also decreases.