Answer:
Higher the inter-molecular attractive force of a compound, higher the energy required to break those bonds. Therefore, their boiling points are higher.
Step-by-step explanation:
The molecules of liquid are free to move in their lattice. But they cannot, leave their lattice or layer, because of the inter-molecular attractive forces. These forces form a bond among molecules. The boiling point is that temperature at which the molecules of liquid acquire enough energy that they overcome these inter-molecular attractive forces and leave the layers of liquid breaking the bonds. Hence, they are converted to gases. This is the reason that compounds with strong inter-molecular forces require more energy to break bond and hence, their boiling points are higher than compounds with weak inter-molecular attractive forces.