A molecule that has partial charges and tends to mix with water is described as which?

• A. Polar
• B. Nonpolar
• C. Ionic
• D. Covalent

Answer: (A)

Molecules with partial charges are polar. This happens when electrons are pulled more toward one atom, creating a slight negative region and a slight positive region. Water is the classic example, with its oxygen carrying a partial negative charge and its hydrogens carrying partial positive charges. Those partial charges allow strong dipole-dipole interactions and hydrogen bonding with other polar molecules, so such substances dissolve or mix well in water. Nonpolar molecules lack this charge separation, so they don’t interact as effectively with water and don’t mix as readily. Ionic substances involve full charges (ions) and rely on different interactions, while covalent simply describes the type of bond and doesn’t by itself dictate solubility. So, the description fits polar.