What is characteristic of polar molecules?

Polar molecules are characterized by an unequal distribution of electrical charge. This uneven distribution occurs due to the differences in electronegativity between the atoms involved in the molecule. In polar molecules, one end of the molecule tends to have a slight positive charge while the other end has a slight negative charge, creating a dipole.

This property influences many physical characteristics of polar substances, such as their solubility in water and their interactions with other molecules. For example, water is a classic polar molecule, which allows it to dissolve many ionic compounds and other polar substances effectively due to its ability to form hydrogen bonds.

The other options focus on aspects that do not define polar molecules; for instance, equal distribution of electrical charge would define nonpolar molecules, while complete neutrality refers to a lack of charge imbalance rather than an unequal distribution. High stability in reactions doesn't necessarily relate to polarity and can vary significantly regardless of molecular polarity.