A polar molecule is a molecule in which one end of the molecule is slightly positive, while the other end is slightly negative. A diatomic molecule that consists of a polar covalent bond, such as HF, is a polar molecule. The two electrically charged regions on either end of the molecule are called poles, similar to a magnet having a north and a south pole.
Polar molecules orient themselves in the presence of an electric field with the positive ends of the molecules being attracted to the negative plate while the negative ends of the molecules are attracted to the positive plate
Polar molecules result from differences in electronegativity of the atoms in the molecule.
Dipoles that are directly opposite one another cancel each other out.