Polar liquids are made up of covalently bonded molecules that each have a partial positive charge on one end and a partial negative charge on the other end. They can dissolve solids that are made of polar molecules but cannot combine with a substance made of nonpolar molecules.Continue Reading
Polar liquids comprise covalent molecules, where atoms share electrons to form bonds. The electrons in a covalent bond are not equally shared between the atoms of different elements. Elements that have a higher electronegativity tend to pull the shared pair of electrons closer to themselves, obtaining a partial negative charge while leaving the other atoms involved in the covalent bond with a partial positive charge. This creates a permanent dipole moment in the molecule, making it polar. Nonpolar molecules do not have partial charges.
Polar liquids, such as water, are held together by the dipole-dipole attraction between the liquid���s molecules. The partial positive charge of one molecule attracts the partial negative charge of another molecule. The dipole interactions can be disrupted by other polar molecules. For example, when a polar solid is added to a polar liquid, the partial positive charge of a liquid molecule attracts the partial negative charge of the molecules from the solid, thus allowing the solid to dissolve in the liquid.
Nonpolar solids cannot dissolve in a polar liquid because they do not possess partial charges and are not strong enough to disrupt the dipole interactions between the liquid molecules.Learn more about Solutions & Mixtures