When a sodium and carbonate ion-containing compound is used as the reactant, the carbonate anion from sodium bicarbonate or carbonate, reacts with the hydrogen from the carboxyl group (-COOH) in acetic acid, forming carbonic acid. Any of these reactions produce sodium acetate and water. It is sometimes produced in a laboratory experiment by the reaction of acetic acid, commonly in the 5–8% solution known as vinegar, with sodium carbonate ('washing soda'), sodium bicarbonate ('baking soda'), or sodium hydroxide ('lye', or 'caustic soda'). Preparation Ī crystal of sodium acetate trihydrate (length 1.7 centimetres)įor laboratory use, sodium acetate is inexpensive and usually purchased instead of being synthesized. Unlike some types of heat packs, such as those dependent upon irreversible chemical reactions, a sodium acetate heat pack can be easily reused by immersing the pack in boiling water for a few minutes, until the crystals are completely dissolved, and allowing the pack to slowly cool to room temperature. The latent heat of fusion is about 264–289 kJ/kg. The bond-forming process of crystallization is exothermic. By pressing on a metal disc within the heating pad, a nucleation center is formed, causing the solution to crystallize back into solid sodium acetate trihydrate. This solution is capable of cooling to room temperature without forming crystals. When they are heated past the melting point and subsequently allowed to cool, the aqueous solution becomes supersaturated. Sodium acetate trihydrate crystals melt at 58–58.4 ☌ (136.4–137.1 ☏), dissolving in their water of crystallization. Sodium acetate is also used in heating pads, hand warmers, and hot ice. This is useful especially in biochemical applications where reactions are pH-dependent in a mildly acidic range (pH 4–6).Ī hand warmer containing a supersaturated solution of sodium acetate which releases heat upon crystallization Buffer solution Ī solution of sodium acetate (a basic salt of acetic acid) and acetic acid can act as a buffer to keep a relatively constant pH level. Sodium acetate (anhydrous) is widely used as a shelf-life extending agent, pH control agent It is safe to eat at low concentration.

It is often used to give potato chips a salt and vinegar flavour, and may be used as a substitute for vinegar itself on potato chips as it doesn’t add moisture to the final product. Sodium acetate may be added to food as a seasoning, sometimes in the form of sodium diacetate, a one-to-one complex of sodium acetate and acetic acid, given the E-number E262. 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. In processing cotton for disposable cotton pads, sodium acetate is used to eliminate the buildup of static electricity. It is also a pickling agent in chrome tanning and helps to impede vulcanization of chloroprene in synthetic rubber production. Sodium acetate is used in the textile industry to neutralize sulfuric acid waste streams and also as a photoresist while using aniline dyes. Sodium acetate is also useful for increasing yields of DNA isolation by ethanol precipitation. Sodium acetate is used as the carbon source for culturing bacteria.

Sodium acetate molar mass