A polar molecule forms when an atom of high electronegativity (one that attracts electrons), such as chlorine, bonds with a less electronegative atom such as hydrogen. Because the more electronegative atom pulls the electron(s) away from the other atom, the molecule formed has one end which is negatively charged and another which is positively charged. Polar molecules tend to align themselves because the negative end of each molecule is attracted to the positive end of other molecules, and vice versa.
HELP PLZ How are polar molecules formed??