Sodium acetate

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Sodium acetate
Sodium acetate
Ball-and-stick model of the acetate anion The sodium cation
Acetate de sodium hydraté.jpg
CAS number 127‑09‑3 N, 6131‑90‑4 (trihydrate)
PubChem 517045
ChemSpider 29105 YesY
ChEBI CHEBI:32954 YesY
RTECS number AJ4300010 (anhydrous)
ATC code B05XA08
Jmol-3D images Image 1
Molecular formula C2H3NaO2
Molar mass 82.03 g mol−1
Appearance White deliquescent powder
Odor Vinegar
Density 1.528 g/cm3
1.45 g/cm3 (trihydrate)
Melting point 324 °C (anhydrous)
58 °C (trihydrate)
Boiling point 881.4 °C (anhydrous)
122 °C (trihydrate, decomposes)
Solubility in water 36.2 g/100 mL (0 °C)
46.4 g/100 mL (20 °C)
139 g/100 mL (60 °C)
170.15 g/100 mL (100 °C)
Solubility Soluble in ethanol (5.3 g/100 mL , trihydrate)
Basicity (pKb) 9.25
Refractive index (nD) 1.464
Crystal structure Monoclinic
MSDS External MSDS
Main hazards Irritant
NFPA 704
Related compounds
Other anions Sodium formate
Sodium propionate
Other cations Potassium acetate
Calcium acetate
Related compounds Sodium diacetate
Infobox references

Sodium acetate, C2H3NaO2, also abbreviated NaOAc,[1] also known as sodium ethanoate, is the sodium salt of acetic acid. This colourless salt has a wide range of uses.




Concrete longevity[edit]

Sodium acetate is used to mitigate water damage to concrete by acting as a concrete sealant, while also being environmentally benign and cheaper than the commonly-used epoxy alternative for sealing concrete against water permeation.[2]


Sodium acetate may be added to food as a seasoning. It may be implemented in the form of sodium diacetate, a one-to-one complex of sodium acetate and acetic acid,[3] given the E-number E262. One frequent instance of use is to impart a salt and vinegar flavor to potato chips.

Buffer solution[edit]


Heating pad[edit]

Sodium acetate is also used in heating pads, hand warmers, and hot ice. Sodium acetate trihydrate crystals melt at 137.12 °F/58.4 °C,[4] (to 136.4 °F/58 °C)[5] dissolving in their water of crystallization. When they are heated past the melting point and subsequently allowed to cool, the aqueous solution becomes supersaturated. This solution is capable of cooling to room temperature without forming crystals. By pressing on a metal disc within the heating pad, a nucleation centre is formed, causing the solution to crystallize back into solid sodium acetate trihydrate. The bond-forming process of crystallization is exothermic.[6][7] The latent heat of fusion is about 264–289 kJ/kg.[5] Unlike some types of heat packs, such as those dependent upon irreversible chemical reactions, sodium acetate heat packs can be easily reused by dissolving the crystals in boiling water for a few minutes until the crystals are completely dissolved.[8]



a crystal of sodium acetate trihydrate (length 1.7 centimetres)

For laboratory use, sodium acetate is inexpensive and usually purchased instead of being synthesized. It is sometimes produced in a laboratory experiment by the reaction of variable concentration acetic acid, commonly known in its 5–8% solution as vinegar, with sodium carbonate ("washing soda"), sodium bicarbonate ("baking soda"), or sodium hydroxide ("lye"). Any of these reactions produce sodium acetate and water. When a sodium and carbonate ion-containing compound is used as the reactant, the carbonate anion is displaced from sodium bicarbonate or carbonate, as is the monatomic hydrogen from the hydroxide in acetic acid, forming the intermediate carbonic acid. Carbonic acid readily decomposes under normal conditions into gaseous carbon dioxide and water. This is the reaction taking place in the well-known "volcano" that occurs when the household products, baking soda and vinegar, are combined.

+ H






Caesium salts catalyze this reaction.


  3. ^ Jungbunzlauer - General Information
  4. ^ [Courty JM, Kierlik E, Les chaufferettes chimiques, Pour la Science, décembre 2008, p 108-110]
  6. ^ "Crystallization of Supersaturated Sodium Acetate". Journal of Chemical Education. 
  7. ^ Fake latent heat and supersaturation

External links[edit]