Sodium hydroxide
Also called lye, caustic soda, soda lye and sodium hydrate.
Lye, the caustic base of drain cleaner and oven cleaner, and the thing that turns fat into soap. It is corrosive to skin on contact.
Sources and notes
- The introductionfrom sourceMoleculeFinder curated
- Other namesfrom sourceWikidataIts English label and aliases on Wikidata.
- Formula and weightcomputedPubChem
- 2D drawingcomputedPubChem structure, drawn by RDKit
Where you encounter it
Sodium hydroxide on our curated lists, and on the product labels we hold.
Every product and list we hold
Sources and notes
- Our curated lists and their amountsfrom sourceMoleculeFinder curatedEach amount is an editorial figure from our food and drink lists, not a measurement of any one product.
- The product labels and their strengthsfrom sourceDailyMed (FDA label)Each label lists the molecule as an ingredient, and an active ingredient at the strength shown.
- How it gets therefrom sourceMoleculeFinder curatedEach mark is set by hand on our lists, never inferred; a label's ingredient is added by the maker. A row with no mark data says Not marked.
What it does
Sodium hydroxide is caustic soda, strong enough to saponify fat and dissolve hair, which is what makes it the active ingredient in drain cleaner and in soap making.
Sources and notes
- The sentencefrom sourceMoleculeFinder comparison notesWord for word from the Sodium hydroxide vs Sodium bicarbonate notes.
Compare a related molecule
Sodium hydroxide
Sodium bicarbonate
Sodium bicarbonate is a weak alkali mild enough to eat, while sodium hydroxide is caustic soda, strong enough to dissolve fat and hair and corrosive to skin.
Sodium hydroxide vs Sodium bicarbonate, side by sideSources and notes
- The sentencefrom sourceMoleculeFinder comparison notesThe pair's answer line.
- The two drawingscomputedPubChem structures, drawn by RDKitThe two drawings side by side.
Properties and sources
Calculated by PubChem
- Molecular formula
- HNaO
- Molecular weight
- 39.997 g/mol
- Polar surface areatopological
- 1 Ų
- H-bond donors
- 1
- H-bond acceptors
- 1
- Rotatable bonds
- 0
- Complexity
- 2
Measured LD50, HSDB via PubChem
40 mg/kg pure sodium hydroxide, mouse, another route
An LD50 is an animal study measurement, not a dose for a person.
Reported Hazard label (GHS), ECHA, EU CLP Regulation, Safe Work Australia via PubChem
Danger Corrosive pictogram (GHS05) and Irritant pictogram (GHS07); hazard statements H290, H314, H315, H318, H319, H335
Groups it belongs to
- Category
- Everyday chemistry
- Family
- Inorganic compounds
- Product lists
- Household cleaners
- Elements
- Sodium
- Hazard classes
- Corrosive, Irritant, GHS Danger
- Size
- Under 100 g/mol
[OH-].[Na+]PubChem CID 14798 · Wikidata Q102769 · InChIKey HEMHJVSKTPXQMS-UHFFFAOYSA-M · Data refreshed
Questions
- What is Sodium hydroxide?
- Lye, the caustic base of drain cleaner and oven cleaner, and the thing that turns fat into soap. It is corrosive to skin on contact.
- Where is Sodium hydroxide found?
- Sodium hydroxide is in these product groups: household cleaners. from source
- How toxic is Sodium hydroxide?
- The reported LD50 of Sodium hydroxide is 40 mg/kg (mouse, other). An LD50 is an animal study measurement, not a dose for a person. Its GHS hazard label carries the signal word Danger and the hazard pictograms Corrosive and Irritant. from sourcefrom source
- What kind of molecule is Sodium hydroxide?
- Sodium hydroxide has the formula HNaO and a molecular weight of 39.997 g/mol. MoleculeFinder files it under inorganic compounds, in the everyday chemistry group. from sourcefrom sourcefrom sourcefrom source
- What else is Sodium hydroxide called?
- Sodium hydroxide is also called caustic soda, lye, soda lye and sodium hydrate. from source
Sources and notes
- Calculated valuescomputedPubChemComputed from the structure, so no laboratory conditions apply; complexity is PubChem's own structural score.
- LD50from sourceHSDB via PubChemOther values the sources report: rabbit, on the skin, 1,350 mg/kg. The page shows the one LD50 the site uses everywhere.
- Hazard labelfrom sourceECHA, EU CLP Regulation, Safe Work Australia via PubChemThe label combines these classifications.
- ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
- EU CLP Regulationfrom sourceAttributionSource: EUR-Lex, Regulation (EC) No 1272/2008, © European Union.
- Safe Work Australiafrom sourceAttributionSource: Safe Work Australia, Hazardous Chemical Information System, © Commonwealth of Australia, CC BY 4.0.
- Data refreshedfrom sourceMoleculeFinder2026-11-09
Keep exploring
Sources and notes
- Compared side by sidefrom sourceMoleculeFinder comparison notesA molecule we compare it with on its own page.
- The drawingscomputedPubChem structures, drawn by RDKit