Sodium bisulfate

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Sodium bisulphate
One sodium cation and one hydrogensulfate anion Ball-and-stick model of the component ions
Sodium bisulfate, as a white powder, turns indicator paper red.
Identifiers
CAS number 7681-38-1 YesY, 10034-88-5 (monohydrate)
PubChem 516919
ChemSpider 56397 YesY
EC number 231-665-7
RTECS number VZ1860000
Jmol-3D images Image 1
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) 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
Structure
Crystal structure triclinic (anhydrous)
monoclinic (monohydrate)
Hazards
MSDS External MSDS
EU Index Corrosive (C)
R-phrases R34 R37 R41
S-phrases S26 S36 S37 S39 S45
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions Sodium sulfate
Other cations Potassium bisulfate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Sodium bisulfate, also known as sodium hydrogen sulfate is the sodium salt of the bisulfate anion, with the molecular formula NaHSO4. Sodium bisulfate is an acid salt formed by partial neutralization of sulfuric acid by an equivalent of sodium, typically either in the form of sodium hydroxide or sodium chloride. 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[edit]

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.

Uses[edit]

Sodium bisulfate is used primarily to lower pH. For technical-grade applications, it is used in metal finishing, cleaning products,[1] 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.

It is highly toxic to at least some echinoderms, but fairly harmless to most other life forms; sodium bisulfate is used in controlling outbreaks of crown-of-thorns starfish.

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] Sodium bisulfate was the primary active ingredient in crystal toilet bowl cleaners Vanish and Sani-Flush, both now discontinued.[3]

In food[edit]

Sodium bisulfate is used as a food additive 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. While one of the manufacturing companies (Jones-Hamilton Co) applied to the FDA to have it considered as generally recognized as safe (GRAS) by the FDA[4] in 1998 however it is not listed on the FDA Food Additives Status List.[5] The food-grade product meets the requirements set out in the Food Chemicals Codex. It is denoted by E number E514ii in the EU and is approved for use in Australia and New Zealand[6] 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[7] (Bisulfate of soda, Sodium bisulfate, Sodium acid sulfate, Mono sodium hydrogen sulfate, Monosodium salt, Sodium hydrogen sulfate, Sodium hydrosulfate, Sodium pyrosulfate, Sulfuric acid, Sulfuric acid sodium salt (1:1)).

References[edit]

  1. ^ John Toedt, Darrell Koza, Kathleen Van Cleef-Toedt Chemical Composition of Everyday Products p.147
  2. ^ Fisch, Arline M. (2003), Textile Techniques in Metal: For Jewelers, Textile Artists & Sculptors, Lark Books, p. 32, ISBN 978-1-57990-514-9. 
  3. ^ SANI-FLUSH® Powder (Discontinued), Reckitt Benckiser.
  4. ^ FDA GRAS Notice
  5. ^ Food Additives Listings
  6. ^ Australia New Zealand Food Standards Code
  7. ^ Noshly

Further reading[edit]