Question

Which of the following statements is correct if the intermolecular forces in liquids A, B and C are in the order \[A < B < C\]?
(A) B evaporates more readily than A
(B) B evaporates less readily than C
(C) A and B evaporate at the same time
(D) A evaporates more readily than C

Answer 1

Hint: We know higher the intermolecular force makes it more difficult to break the molecular bonds. Now if the intermolecular bonds are weakened, only then the particles will move more freely. If the particles are able to move freely so that they can escape the bulk, then they can evaporate.

Complete step by step answer::
Evaporation is the process in which the surface molecules of a liquid gain kinetic energy and escape in the form of vapor. If we will increase the intermolecular forces then the force between the molecules will also increase and as a result the escaping tendency will decrease. This means that higher the intermolecular forces lower will be the escaping tendency of the molecules.
Hence, we can say that if a particle has a low escaping tendency then the rate of evaporation for that particle will be low. So, we conclude that:
If intermolecular forces are high, escaping tendency will be low and the rate of evaporation will also decrease.
The order for intermolecular forces in a liquid as per the question is \[A < B < C\]. Therefore, the rate of evaporation will be \[A > B > C\]. This means that A will evaporate more readily than C.

So, the correct option is option (d.).

Note: The nature of molecules is different in different mediums. One should know the medium while working on these conditions.
It is vital that one understands the difference between evaporation and boiling. In boiling, almost all the particles in the bulk are heated to the extent that they gain kinetic energy equal to a gas particle, but in evaporation this only the particles on the surface that is open will be able to escape in the form of vapors.