Ascorbic acid is an organic compound with formula C
6, originally called hexuronic acid. It is a white solid, but impure samples can appear yellowish. It dissolves well in water to give mildly acidic solutions. It is a mild reducing agent.
Ascorbic acid exists as two enantiomers (mirror-image isomers), commonly denoted “l” (for “levo”) and “d” (for “dextro”). The l isomer is the one most often ecountered: it occurs naturally in many foods, and is one form (“vitamer“) of vitamin C, an essential nutrient for humans and many animals. Deficiency of vitamin C causes scurvy, formerly a major disease of sailors in long sea voyages. It is used in as a food additive and a dietary supplement for its antioxidant properties. The “d” form can be made via chemical synthesis but has no significant biological role.