Sodium bisulfate

Sodium bisulfate
Sodium bisulfate
CAS number 7681-38-1 YesY, 10034-88-5 (monohydrate)
PubChem 7681-38-1
EC number 231-665-7
RTECS number VZ1860000
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) at 315°C

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
Crystal structure triclinic (anhydrous)
monoclinic (monohydrate)
MSDS External MSDS
EU Index Corrosive (C)
R-phrases R34 R37 R41
S-phrases S26 S36 S37 S39 S45
NFPA 704
NFPA 704.svg
Flash point Non-flammable
Related compounds
Other anions Sodium sulfate
Other cations Potassium bisulfate
 YesY bisulfate (verify) (what is: YesY/N?)
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.

One production 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.


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 (Generally Recognized As Safe) by FDA[1] 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.

In jewelry making, sodium bisulfate is the primary ingredient used in many pickling solutions to remove the oxidation layer from surfaces, which occurs after heating.[2]

Highly toxic to at least some echinoderms but fairly harmless to most other lifeforms, sodium bisulfate is used in controlling outbreaks of crown-of-thorns starfish.


Further reading

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Look at other dictionaries:

  • sodium bisulfate — noun also sodium acid sulfate : a crystalline salt NaHSO4 that gives an acid reaction in solution, that is usually made by the reaction of sulfuric acid with common salt or sodium sulfate, and that is used chiefly as a flux in pickling metals and …   Useful english dictionary

  • sodium bisulfate — Chem. a colorless crystalline compound, NaHSO4, soluble in water: used in dyeing, in the manufacture of cement, paper, soap, and an acid type cleaner. Also called sodium hydrogen sulfate. * * * …   Universalium

  • Sodium sulfate — Other names …   Wikipedia

  • Sodium bicarbonate — Sodium bicarbonate …   Wikipedia

  • Sodium bisulfite — Sodium bisulfite …   Wikipedia

  • Sodium nitrate — IUPAC name …   Wikipedia

  • Sodium dithionite — Sodium dithionite …   Wikipedia

  • sodium sulfate — noun a solid white bitter salt used in manufacturing glass and paper and dyes and pharmaceuticals • Syn: ↑sodium sulphate • Hypernyms: ↑sulfate, ↑sulphate * * * noun : either of two crystalline sulfates of sodium: a …   Useful english dictionary

  • bisulfate — /buy sul fayt/, n. Chem. a salt of sulfuric acid, containing the HSO4 group; an acid sulfate; a hydrogen sulfate, as sodium bisulfate, NaHSO4. Also, bisulphate. [1860 65; BI 1 + SULFATE] * * * …   Universalium

  • sodium hydrogen sulfate — Chem. See sodium bisulfate. * * * …   Universalium

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