Sodium bisulfate, also known as sodium hydrogen sulfate, is the

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

salt of the bisulfate anion, with the molecular formula NaHSO₄. Sodium bisulfate is an acid salt formed by partial neutralization of

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

by an equivalent of sodium base, typically in the form of either

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

(lye) or

sodium chloride Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...

(table salt). It is a dry granular product that can be safely shipped and stored. The anhydrous form is hygroscopic. Solutions of sodium bisulfate are acidic, with a 1M solution having a pH of slightly below 1.

Production

Sodium bisulfate is produced as an intermediate in the Mannheim process, an industrial process involving the reaction of

and

: : The process for the formation of sodium bisulfate is highly exothermic. The liquid sodium bisulfate is sprayed and cooled so that it forms a solid bead. The hydrogen chloride gas is dissolved in water to produce hydrochloric acid as a useful coproduct of the reaction. Sodium bisulfate can be generated as a byproduct of the production of many other mineral acids via the reaction of their sodium salts with an excess of

: :NaX + H₂SO₄ → NaHSO₄ + HX ( X⁻ = CN⁻, NO₃⁻, ClO₄⁻) The acids HX produced have a lower boiling point than the reactants and are separated from the reaction mixture by distillation.

Chemical reactions

Hydrated sodium bisulfate dehydrates at at which point it separates from the water molecule attached to it. Once cooled again, it is freshly hygroscopic. Heating sodium bisulfate to produces sodium pyrosulfate, another colorless salt: :

Uses

Sodium bisulfate is used primarily to lower pH. It is also used in metal finishing, cleaning products, and to lower the pH of water for effective chlorination in swimming pools and hot tubs. Sodium bisulfate is also AAFCO approved as a general-use feed additive, including use in poultry feed and companion animal food. It is used as a urine acidifier to reduce urinary stones in cats. It is highly toxic to certain

echinoderm An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as ...

s, but fairly harmless to most other life forms; so it is used in controlling outbreaks of crown-of-thorns starfish. Sodium bisulfate was the primary active ingredient in the toilet bowl cleaners Vanish and Sani-Flush, both now discontinued. In the textiles industry, it is sometimes applied to

velvet Velvet is a type of woven fabric with a dense, even pile (textile), pile that gives it a distinctive soft feel. Historically, velvet was typically made from silk. Modern velvet can be made from silk, linen, cotton, wool, synthetic fibers, silk ...

cloth made with a silk backing and a pile of cellulose-based fiber (rayon, cotton, hemp, etc.) to create "burnout velvet": the sodium bisulfate, when applied to such a fabric and heated, causes the cellulose-based fibers to become brittle and flake away, leaving burned-out areas in the finished material, usually in attractive patterns. Sodium bisulfate is the active ingredient in some granular poultry litter treatments used to control ammonia. Sodium bisulfate has also been shown to significantly reduce the concentration of ''Campylobacter'' and ''Salmonella'' in chicken houses. Sodium bisulfate is sometimes used as the active ingredient in flocculant tablets, a step in soil and water quality test kits.

In food

Sodium bisulfate is used as a

food additive Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives, such as vinegar ( pickling), salt ( salting), smoke ( smoking) and sugar ( crystallization), have been used f ...

to leaven cake mixes (make them rise) as well as being used in meat and poultry processing and most recently in browning prevention of fresh-cut produce. Sodium bisulfate is considered

generally recognized as safe Generally recognized as safe (GRAS) is a United States Food and Drug Administration (FDA) designation that a chemical or substance added to food is considered safe by experts under the conditions of its intended use. An ingredient with a GRAS d ...

(GRAS) by the FDA and has been named to the EPA Safer Choice Safer Chemicals Ingredients List. The food-grade product also meets the requirements set out in the Food Chemicals Codex. It is denoted by

E number E numbers, short for Europe numbers, are codes for substances used as food additives, including those found naturally in many foods, such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

E514ii in the EU and is also approved for use in Australia, New Zealand, Canada, and Mexico. where it is listed as additive 514. Food grade sodium bisulfate is used in a variety of food products, including beverages, dressings, sauces, and fillings. It has many synonyms including bisulfate of soda, sodium acid sulfate, mono sodium hydrogen sulfate, sodium hydrogen sulfate, sodium hydrosulfate, and sulfuric acid sodium salt (1:1). Sodium bisulfate lowers the pH without creating a sour taste, and has been used in the place of citric, malic, or phosphoric acids that are commercially available, and it can also be used as an anti-browning agent.

Notes

The "bi" refers to the presence of the hydrogen.

References

External links

Food Chemicals Codex
{{Sulfates Sulfates Sodium compounds Acid salts Photographic chemicals Cleaning products Food additives