Question

Why does mercury not evaporate at room temperature?
(A) Because melting point of mercury is higher
(B) Because boiling point of mercury is higher
(C) Because boiling point of mercury is lower
(D) Because boiling point of mercury is equal to room temperature

Answer 1

Hint
We know that mercury does not evaporate at room temperature. It has its various applications like it is used in thermometers to check body temperatures also. We will see that mercury has a higher boiling point that is why it does not show the evaporation process at room temperature.

Complete step by step answer
Evaporation: it involves conversion of liquid state molecules into gaseous state molecules.
When heat is given to particles, they gain energy. On gaining enough energy, particles start moving randomly to acquire kinetic energy and get mixed up with the particles present in air. It is a surface phenomenon.
But not all particles show this behavior. One such example is mercury. These kinds of substances need more energy to reach an environmental state. Heat is provided to increase the temperature of liquid, force of attraction between molecules starts to decrease and almost become negligible and they separate out.
Boiling point: when the liquid pressure becomes equal to pressure neighboring the liquid; temperature at which this pressure becomes equal is known as boiling point. It is a bulk phenomenon.
Melting point: it is used to change solid state substances into liquid state.
But mercury is already present in the liquid state.
So, the correct option is (B).

Note
If boiling point is lower than mercury should evaporate at room temperature. But this doesn’t happen (option (C) is wrong).
If the melting point is higher than the larger amount of heat given should be used up in converting it into liquid state but it is already in that state (which does not satisfy option (A)).
If boiling point becomes equal to room temperature then it should evaporate at room temperature but this does not happen (which does not satisfy option (D)).
Hence, we are left with only one correct part that is option (B).