CoachA species or a part of a molecule is hydrophilic if it is attracted by water (ionic or polar groups, groups that form hydrogen bonds); it is hydrophobic if it is not (long chains of carbon and hydrogen atoms, non-polar). Hydrophobic species dissolve in fats and oils.
Examples
Example 31.10 (A soap)
Sodium stearate, (), is a typical soap, made from animal or vegetable fats. In water it dissolves as sodium ions and stearate ions : a head , ionic, hydrophilic, and a tail of 17 carbon atoms, hydrophobic.