ascorbic acid is a sugar acid. it is white to light-yellow in colour, and comes in the form of crystals or powder. it is water-soluble. ascorbic acid is one form of vitamin c, and was historically the first chemical compound to be synthesized, and identified, as vitamin c. the name is derived from a- (meaning "no") and scorbutus (scurvy), the disease caused by a deficiency of vitamin c.