The freezing point, boiling point, density, viscosity all are controlled by intermolecular attractions. The higher the attractions (forces) the higher the melting point, boiling point, density and viscosity.Evaporation is a process where a liquid converts to the gas through the gradual escape of molecules from the liquid to the gas at temperatures below the boiling point.he freezing point, boiling point, density, viscosity all are controlled by intermolecular attractions. The higher the attractions (forces) the higher the melting point, boiling point, density and viscosity.