A molecular dipole occurs when there is a separation of positive and negative charges within a molecule, resulting in a dipole moment. This happens when atoms in a molecule have different electronegativities, causing uneven sharing of electrons. The end with higher electronegativity becomes partially negative, while the other end becomes partially positive. Molecular dipoles are important in understanding molecular interactions, such as hydrogen bonding and solubility. Molecules with significant dipoles tend to interact strongly with polar solvents, while nonpolar molecules do not exhibit dipole moments and are more soluble in nonpolar solvents.