In chemistry, a zwitterion, also called an inner salt, is a molecule that contains an equal number of positively- and negatively-charged functional groups. A zwitterion is a molecule that has at least two functional groups: one having a positive charge and the other having a negative charge, with an overall charge of zero. In chemistry, a zwitterion also called an inner salt, is a molecule that contains an equal number. “A zwitterion is a molecule that has both positive and negative regions of charge. Zwitterion, also known as inner salt or dipolar ion, is an ion with a positive and a negative electrical charge at different locations within a molecule. Thus, there are two ammonium ions and only one carboxylate ion.