Ethanol
Ethanol is a molecule-level alcohol example; under alkaline iodine it is oxidised and cleaved to triiodomethane and methanoate.
- Formula
- C2H6O
- Functional group
- CH3CH2OH
- Molar mass
- 46.07 g/mol
- Also known as
- ethyl alcohol, CH3CH2OH, C2H5OH
Overview
Two-carbon primary alcohol that gives the iodoform reaction.
Ethanol is a molecule-level alcohol example; under alkaline iodine it is oxidised and cleaved to triiodomethane and methanoate.
Identifiers
- Formula
- C2H6O
- Functional group
- CH3CH2OH
- Molar mass
- 46.07 g/mol
- Also known as
- ethyl alcohol, CH3CH2OH, C2H5OH
Chemical identifiers
- SMILES
- CCO
- InChI
- InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3
- PubChem CID
- 702
Properties
- Melting Point
- -114.14 °C
- Boiling Point
- 78.24 °C
- Density
- 0.7893 g/cu cm at 20 °C
- Water solubility
- Miscible with water at 25 °C
Diagnostic tests
iodoform test
- Reagent
- iodine in alkaline solution
- Conditions
- Add iodine followed by aqueous alkali and warm gently in a water bath.
- Positive observation
- a pale-yellow precipitate of triiodomethane forms
- Negative observation
- no pale-yellow precipitate forms
- Interpretation
- A positive result is consistent with ethanol, which is first oxidised to ethanal under the test conditions.
- Scope
- Ethanol is the primary-alcohol exception that gives the iodoform reaction.
- Limitations
- Not unique to ethanol: ethanal, methyl ketones and methyl secondary alcohols also give a positive result.
- Evidence
- textbook core
Related compounds
- Alcohols
Ethanol is a molecule-level primary alcohol within the alcohol family.
Connected reactions
- Iodoform reaction: Ethanol → Triiodomethane products
Ethanol is oxidised and cleaved by alkaline iodine to give triiodomethane and methanoate.
- Partial oxidation: Ethanol → Ethanal
Ethanol is oxidised to ethanal.
- Oxidation: Ethanol → Ethanoic acid
Ethanol is oxidised to ethanoic acid.
- Reduction: Ethanal → Ethanol
Ethanal is reduced to ethanol.
- Esterification: Ethanol → Ethyl acetate
Ethanoic acid and ethanol combine reversibly to form ethyl acetate and water.
- Acid hydrolysis: Ethyl acetate → Ethanol
Ethyl acetate and water react reversibly to form ethanoic acid and ethanol.
- Hydration: Ethene → Ethanol
Ethene gives ethanol through hydration.
- Dehydration: Ethanol → Ethene
Ethanol gives ethene through dehydration.
- Intermolecular dehydration: Ethanol → Diethyl ether
Protonation turns one ethanol OH group into a better leaving group. The oxygen of another ethanol molecule displaces water, and deprotonation gives diethyl ether; stronger dehydration conditions instead favour ethene.
- Hydrolysis: Bromoethane → Ethanol
Hydroxide attacks the saturated carbon bearing bromine while the C-Br bond breaks. This primary-substrate SN2 route replaces bromide with OH and preserves both carbon atoms; aqueous conditions favour this branch over elimination.
- Acid hydrolysis: Ethyl butyrate → Ethanol
Water attack and proton transfers permit the ethoxy fragment to leave as ethanol. Re-forming the carbonyl produces butanoic acid on the other branch.
References
- PubChem Compound Summary for EthanolNational Center for Biotechnology Information · PubChem · 2026
Used for stable identifiers and basic compound metadata.
- Hazardous Substances Data Bank (HSDB): Ethanol — melting pointHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/702#section=Melting-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. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-246
- Hazardous Substances Data Bank (HSDB): Ethanol — boiling pointHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/702#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. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-246
- Hazardous Substances Data Bank (HSDB): Ethanol — densityHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/702#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. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-246
- Hazardous Substances Data Bank (HSDB): Ethanol — solubilityHazardous Substances Data Bank (HSDB)
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/702#section=Solubility. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Riddick, J.A., W.B. Bunger, Sakano T.K. Techniques of Chemistry 4th ed., Volume II. Organic Solvents. New York, NY: John Wiley and Sons., 1985., p. 192
- Pearson Edexcel International Advanced Level Chemistry Practical GuidePearson Education Limited · Pearson qualifications · 2018
Official Pearson practical guidance for organic qualitative tests, including bromine water, acidified dichromate, silver nitrate, carbonyl reagents and the iodoform reaction.