Question

Which of the following statements is incorrect?
(A) Melting point and Freezing point of the substance are the same.
(B) Evaporation of liquid takes place only at its boiling point.
(C) Pure water has no taste.
(D) Water allows the sunlight to pass through it.

Answer 1

Hint: Evaporation is an endothermic process and it is a surface phenomenon, i.e., the surface molecule takes part in the evaporation process. The surface molecules are in direct contact with the surrounding atmosphere so they absorb and accumulate the energy from the surrounding and evaporate in the surrounding therefore it does not require any specific temperature for evaporation.

Complete step by step answer:.
First let us understand what melting point , boiling point and freezing point .
Melting point : The temperature at which The solid and liquid states of a substance coexist in thermal equilibrium with each other is called its melting point . It is a characteristic of the substance but also depends on pressure. The melting point of a substance at Standard atmospheric pressure is called its normal melting point.
Also the freezing point of a substance is the temperature at which liquid starts changing its state from liquid to solid . Thus , the liquid and solid phase coexist at this point .
Hence , we can say that melting and freezing points of a substance are the same .
Boiling point : The temperature at which the liquid and vapour states of a substance coexist in thermal equilibrium with each other Is called its boiling point .
Evaporation is a surface phenomenon , that is the molecules present at the surface evaporate because of the energy they get from the random movement of particles . Evaporation can take place at any place , it doesn't have to be necessarily boiling point .
Hence the incorrect statement is option B .
It is true that pure water has no taste . Also water allows sunlight to pass through it because of its transparency .

So, the correct answer is Option B.

Note: Evaporation can take place at all temperatures but its rate depends upon the surrounding atmosphere. Higher the temperature higher will be the rate of evaporation. Similarly it also depends upon the wind speed or velocity, surface area and nature of the solvent molecules too.