<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2015) (Learn how and when to remove this template message) </Td> </Tr> <P> In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment . </P> <P> Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms . A polar molecule with two or more polar bonds must have a geometry which is asymmetric in at least one direction, so that the bond dipoles do not cancel each other . </P> <P> Polar molecules interact through dipole--dipole intermolecular forces and hydrogen bonds . Polarity underlies a number of physical properties including surface tension, solubility, and melting and boiling points . </P>

For a molecule to be polar it must have