L

Lactic acid

IUPAC: 2-hydroxypropanoic acid

C3H6O3 Acids CAS 50-21-5
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Quick Reference
Formula / NotationC3H6O3
CAS Number50-21-5
Molecular Weight90.08
Melting Point16.8 °C
Boiling Point122 °C at 1.50E+01 mm Hg
Density1.2 at 68 °F (USCG, 1999) - Denser than water; will sink
Solubility1000000 mg/L
AppearanceLactic acid appears as a colorless to yellow odorless syrupy liquid. Corrosive to metals and tissue. Used to make cultured dairy products, as a food preservative, and to make chemicals.
Also Known As2-hydroxypropanoic acid; DL-Lactic acid; 50-21-5; 2-hydroxypropionic acid; Milk acid; Tonsillosan; Racemic lactic acid; Ordinary lactic acid; Acidum lacticum; Ethylidenelactic acid
CategoryAcids

What is Lactic acid?

2-hydroxypropanoic acid is a 2-hydroxy monocarboxylic acid that is propanoic acid in which one of the alpha-hydrogens is replaced by a hydroxy group. It has a role as a Daphnia magna metabolite and an algal metabolite. It is functionally related to a propionic acid. It is a conjugate acid of a lactate.

Formula & Notation

C3H6O3

IUPAC Name: 2-hydroxypropanoic acid

Other Names / Synonyms: 2-hydroxypropanoic acid; DL-Lactic acid; 50-21-5; 2-hydroxypropionic acid; Milk acid; Tonsillosan; Racemic lactic acid; Ordinary lactic acid; Acidum lacticum; Ethylidenelactic acid

Properties & Characteristics

Appearance: Lactic acid appears as a colorless to yellow odorless syrupy liquid. Corrosive to metals and tissue. Used to make cultured dairy products, as a food preservative, and to make chemicals.. Molecular formula: C3H6O3. Molecular weight: 90.08 g/mol. Boiling point: 122 °C at 1.50E+01 mm Hg. Melting point: 16.8 °C. Density: 1.2 at 68 °F (USCG, 1999) - Denser than water; will sink. Solubility: 1000000 mg/L. Vapor pressure: 0.08 [mmHg]. LogP: -0.7.

Physical Data

PropertyValue
Melting Point16.8 °C
Boiling Point122 °C at 1.50E+01 mm Hg
Density1.2 at 68 °F (USCG, 1999) - Denser than water; will sink
Molecular Weight90.08
Solubility1000000 mg/L
AppearanceLactic acid appears as a colorless to yellow odorless syrupy liquid. Corrosive to metals and tissue. Used to make cultured dairy products, as a food preservative, and to make chemicals.

Uses & Applications

Used in industrial chemical synthesis, fertilizer production, battery electrolytes, metal processing, and laboratory acid-base reactions.

Safety Information

Corrosive. Causes severe burns to skin, eyes, and respiratory tract. Wear appropriate PPE including gloves, goggles, and lab coat. Consult SDS before use.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Lactic acid
Formula C3H6O3
CAS Number 50-21-5
Molecular Weight 90.08
Category Acids
Synonyms 2-hydroxypropanoic acid; DL-Lactic acid; 50-21-5; 2-hydroxypropionic acid; Milk acid; Tonsillosan; Racemic lactic acid; Ordinary lactic acid; Acidum lacticum; Ethylidenelactic acid

Frequently Asked Questions

2-hydroxypropanoic acid is a 2-hydroxy monocarboxylic acid that is propanoic acid in which one of the alpha-hydrogens is replaced by a hydroxy group. It has a role as a Daphnia magna metabolite and an algal metabolite. It is functionally related to a propionic acid. It is a conjugate acid of a lactate.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.