A polar solvent cannot dissolve a non-polar solute. This is because polar solvents are attracted to each other through dipole-dipole interactions, while non-polar solutes are not attracted to each other or to the polar solvent. As a result, non-polar solutes will not dissolve in polar solvents.

For example, water is a polar solvent and oil is a non-polar solute. Oil will not dissolve in water because the water molecules are attracted to each other and not to the oil molecules.