As a result, the net intermolecular force on molecules at the surface pulls them towards the interior of the liquid. A liquid's resistance to flow is called its viscosity . Viscosity can be determined by measuring the time it takes for a specific amount of liquid to flow through a tube of known diameter under the force of gravity. Viscosity measures how easily molecules slide by one another and this depends on molecular shapes and intermolecular forces. The solubility of a substance in a particular solvent is the concentration of the saturated solution.
Solubilities vary widely because they depend on the intermolecular forces in the solute and solvent.
K f is the freezing point depression constant . The constant is different for different solvents but does not depend on the identity of the solutes. A boiling point is increased by adding a nonvolatile solute. K b is the boiling point elevation constant . The constant is different for different solvents but does not depend on the identity of the solutes.