Sodium bisulfate

Sodium bisulfate
IUPAC name	Sodium hydrogen sulfate
Other names	Sodium acid sulfate Bisulfate of soda
Identifiers
CAS number	7681-38-1 Y, 10034-88-5 (monohydrate)
PubChem	7681-38-1
EC number	231-665-7
RTECS number	VZ1860000
Properties
Molecular formula	NaHSO4
Molar mass	120.06 g/mol (anhydrous) 138.07 g/mol (monohydrate)
Appearance	white solid
Density	2.742 g/cm3 (anhydrous) 1.8 g/cm3 (monohydrate)
Melting point	58.5°C (monohydrate) 315°C (anhydrous)
Boiling point	decomposes to Na2S2O7 (+ H2O)
Solubility in water	50 g/100 mL (0°C) 100 g/100 mL (100°C)
Solubility	insoluble in ammonia; decomposed by alcohol
Acidity (pKa)	1.99
Structure
Crystal structure	triclinic (anhydrous) monoclinic (monohydrate)
Hazards
EU Index	Corrosive (C)
NFPA 704	0 1 1
Flash point	Non-flammable
Related compounds
Other anions	Sodium sulfate
Other cations	Potassium bisulfate
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium bisulfate, also known as sodium hydrogen sulfate (NaHSO4), is an acid 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 < 1.

Production

Sodium bisulfate is produced by two methods. One method involves mixing stoichiometric quantities of sodium hydroxide and sulfuric acid which react to form sodium bisulfate and water.

NaOH + H₂SO₄ → NaHSO₄ + H₂O

A second production method involves reacting sodium chloride (salt) and sulfuric acid at elevated temperatures to produce sodium bisulfate and hydrogen chloride gas.

NaCl + H₂SO₄ → NaHSO₄ + HCl

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.

There are only two producers in the USA: Jones-Hamilton Co. uses the sulfuric acid/sodium chloride process, which produces the anhydrous form. Jost Chemical uses the sodium hydroxide/sulfuric acid method, which produces the monohydrate.

Uses

Sodium bisulfate is used primarily to lower pH. For technical grade applications it is used in metal finishing, cleaning products, and to lower the pH of water for effective chlorination, including swimming pools. Sodium bisulfate is also AAFCO approved as a general use feed additive, including companion animal food. It is used as a urine acidifier to reduce urinary stones in cats. Sodium bisulfate is considered GRAS by FDA and meets their definition of a natural product. The food grade product meets the requirements set out in the Food Chemicals Codex (FCC). It is denoted by E number E514ii in the EU. Food Grade sodium bisulfate is used in a variety of food products, including beverages, dressings, sauces, and fillings. It is also widely used in meat and poultry processing and most recently in browning prevention of fresh cut produce.

References

Further reading

This article's citation style may be unclear. The references used may be made clearer with a different or consistent style of citation, footnoting, or external linking.

• Monohydrate MSDS
• Monohydrate Product Data
• AAFCO Offical Publication
• Iams Cat Food Ingredients
• U of Illinois Research
• FDA GRAS Notice

• Food Chemicals Codex
• Browning Inhibitor Study