Ethanoic acid
A weak carboxylic acid linking neutralisation, buffers and ester formation.
- Formula
- C2H4O2
- Functional group
- Carboxylic acids
- Molar mass
- 60.05 g/mol
- Also known as
- acetic acid, Ethylic acid, Vinegar acid, Acetic acid glacial, Glacial acetic acid, Acetic acid, glacial
Overview
A weak carboxylic acid linking neutralisation, buffers and ester formation.
Its acidic proton belongs to the carboxyl OH group. Deprotonation produces ethanoate, whose negative charge is delocalised over two oxygen atoms. Weak acid means partial ionisation in water; it does not describe whether an acid solution is concentrated or dilute.
Identifiers
- Formula
- C2H4O2
- Functional group
- Carboxylic acids
- Molar mass
- 60.05 g/mol
- Also known as
- acetic acid, Ethylic acid, Vinegar acid, Acetic acid glacial, Glacial acetic acid, Acetic acid, glacial
Chemical identifiers
- SMILES
- CC(=O)O
- InChI
- InChI=1S/C2H4O2/c1-2(3)4/h1H3,(H,3,4)
- PubChem CID
- 176
Properties
- Melting Point
- 16.635 °C
- Boiling Point
- 117.9 °C
- Density
- 1.0446 g/cu cm at 25 °C
- Water solubility
- Miscible with water
Related compounds
- Carboxylic acids
A weak carboxylic acid linking neutralisation, buffers and ester formation.
Connected reactions
- Oxidation: Ethanol → Ethanoic acid
Ethanol is oxidised to ethanoic acid.
- Oxidation: Ethanal → Ethanoic acid
Ethanal is oxidised to ethanoic acid.
- Esterification: Ethanoic acid → Ethyl acetate
Ethanoic acid and ethanol combine reversibly to form ethyl acetate and water.
- Acid hydrolysis: Ethyl acetate → Ethanoic acid
Ethyl acetate and water react reversibly to form ethanoic acid and ethanol.
- Amide hydrolysis: Acetamide → Ethanoic acid
Acid activates the amide carbonyl for water addition. Proton transfer makes nitrogen a better leaving group before C-N cleavage; the acyl fragment becomes ethanoic acid and the nitrogen ends as ammonium.
- Acid hydrolysis: Methyl acetate → Ethanoic acid
Water adds to the protonated ester carbonyl. Proton transfer allows methanol to leave as the carbonyl reforms, producing the acid and alcohol together.
References
- PubChem Compound Summary: Ethanoic acid (CID 176)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- OpenStax Organic Chemistry: Structure and properties of carboxylic acidsJohn McMurry · OpenStax · 2023
Supports the qualitative structural interpretation of the recorded molecular structure; no new physical measurement or verified preparative yield is claimed.
- Hazardous Substances Data Bank (HSDB): Ethanoic acid — melting pointHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/176#section=Melting-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Wagner FS; Acetic Acid. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2014). New York, NY: John Wiley & Sons. Online Posting Date: Apr 29, 2014.
- Hazardous Substances Data Bank (HSDB): Ethanoic acid — boiling pointHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/176#section=Boiling-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-4
- Hazardous Substances Data Bank (HSDB): Ethanoic acid — densityHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/176#section=Density. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-4
- Hazardous Substances Data Bank (HSDB): Ethanoic acid — solubilityHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/176#section=Solubility. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-4