Vitamin C (Ascorbic Acid) (C₆H₈O₆) — Properties, Uses & Safety

Overview

Vitamin C, also known as ascorbic acid (C6H8O6), is an essential water-soluble vitamin with a molar mass of 176.12 g/mol. Its IUPAC name, (R)-3,4-dihydroxy-5-((S)-1,2-dihydroxyethyl)furan-2(5H)-one, reveals a lactone ring structure with multiple hydroxyl groups that make it highly polar and water-soluble. At standard conditions, vitamin C appears as a white to yellow crystalline solid with a sharp, acidic taste. Humans are among the few mammals that cannot synthesize vitamin C internally due to a mutation in the gene for the enzyme L-gulonolactone oxidase, making dietary intake essential. Rich sources include citrus fruits, strawberries, bell peppers, broccoli, and kiwifruit. Vitamin C is a powerful antioxidant and reducing agent. It donates electrons to neutralize free radicals, protecting cells from oxidative damage. Biologically, it is required for the synthesis of collagen (the most abundant protein in the body), the absorption of iron from the digestive tract, immune system function, and wound healing. Severe deficiency causes scurvy — a disease characterized by bleeding gums, joint pain, and poor wound healing that historically devastated sailors on long voyages. The GHS hazard code H319 (causes serious eye irritation) applies to concentrated forms. Vitamin C is widely used as a dietary supplement and food additive (E300) to prevent oxidation and preserve color in processed foods. For chemistry students, ascorbic acid is a rich teaching molecule. Its role as a reducing agent connects to redox chemistry — it can reduce iodine in titration experiments, providing a classic quantitative analysis exercise for determining vitamin C content in foods and juices. The molecule illustrates stereochemistry with two chiral centers, lactone functional groups, enol-keto tautomerism, and the relationship between molecular structure and biological function. Understanding vitamin C bridges organic chemistry, biochemistry, and nutrition science in an accessible and personally relevant way.

IUPAC Name

(R)-3,4-dihydroxy-5-((S)-1,2-dihydroxyethyl)furan-2(5H)-one

CAS Number

50-81-7

PubChem CID

54670067

Molecular Formula

C₆H₈O₆

Molar Mass

176.124 g/mol

State at STP

solid

Appearance

White to yellow crystalline solid