Sodium bisulfate | |
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Sodium hydrogen sulfate |
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Other names
Sodium acid sulfate |
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Identifiers | |
CAS number | 7681-38-1 , 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) |
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 |
0
1
1
|
Flash point | Non-flammable |
Related compounds | |
Other anions | Sodium sulfate |
Other cations | Potassium bisulfate |
(verify) (what is: / ?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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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.
A second production method involves reacting sodium chloride (salt) and sulfuric acid at elevated temperatures to produce sodium bisulfate and hydrogen chloride gas.
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.