Potassium bisulfate

title: "Potassium bisulfate" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["sulfates", "potassium-compounds", "acid-salts"] topic_path: "general/sulfates" source: "https://en.wikipedia.org/wiki/Potassium_bisulfate" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
| Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 448460445 | ImageFile1 = Potassium bisulfate.png | ImageSize1 = 170px | ImageName1 = One potassium cation and one hydrogensulfate anion | ImageFile2 = Potassium-bisulfate-3D-balls-ionic.png | ImageName2 = Ball-and-stick model of the component ions | ImageFile3 = Hydrogensíran draselný.jpg | ImageName3 = Potassium bisulfate crystals on filter paper | IUPACName = Potassium hydrogen sulfate | OtherNames = Potassium acid sulfate | Section1 = {{Chembox Identifiers |CASNo = 7646-93-7 |CASNo_Ref = |UNII_Ref = |UNII = 1J1K03241F |PubChem = 516920 |RTECS = TS7200000 |UNNumber = 2509 |EINECS = 231-594-1 |SMILES = OS(=O)(=O)[O-].[K+] |ChemSpiderID_Ref = |ChemSpiderID = 56396 |InChI = 1/K.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+1;/p-1 |InChIKey = CHKVPAROMQMJNQ-REWHXWOFAH |StdInChI_Ref = |StdInChI = 1S/K.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+1;/p-1 |StdInChIKey_Ref = |StdInChIKey = CHKVPAROMQMJNQ-UHFFFAOYSA-M | Section2 = {{Chembox Properties |Formula = KHSO4 |MolarMass = 136.169 g/mol |Appearance = colorless solid |Odor = odorless |Density = 2.245 g/cm3 |MeltingPtC = 197 |BoilingPtC = 300 |BoilingPt_notes = (decomposes to form potassium pyrosulfate and water) |Solubility = 36.6 g/100 mL (0 °C) 49 g/100 mL (20 °C) 121.6 g/100 mL (100 °C) |SolubleOther = soluble in acetone, insoluble in ethanol. |MagSus = −49.8·10−6 cm3/mol | Section3 = {{Chembox Thermochemistry |DeltaHf = −1163.3 kJ/mol | Section4 = {{Chembox Hazards |ExternalSDS = External MSDS |LD50 = 2340 mg*kg−1 |GHSPictograms = |GHSSignalWord = Danger |HPhrases = |PPhrases = | Section5 = {{Chembox Related |OtherCompounds = Potassium sulfate Sodium bisulfate
Potassium bisulfate (potassium bisulphate) is an inorganic compound with the chemical formula KHSO4 and is the potassium acid salt of sulfuric acid. It is a white, water-soluble solid.
Preparation
More than 1 million tons were produced in 1985 as the initial stage in the Mannheim process for producing potassium sulfate. The relevant conversion is the exothermic reaction of potassium chloride and sulfuric acid: :
Potassium bisulfate is a by-product in the production of nitric acid from potassium nitrate and sulfuric acid: :
Chemical properties
Thermal decomposition of potassium bisulfate forms potassium pyrosulfate: :
Above 600 °C potassium pyrosulfate converts to potassium sulfate and sulfur trioxide: :
Uses
Potassium bisulfate is commonly used to prepare potassium bitartrate for winemaking. Potassium bisulfate is also used as a disintegrating agent in analytical chemistry or as a precursor to prepare potassium persulfate, a powerful oxidizing agent.
Occurrence
Mercallite, the mineralogical form of potassium bisulfate, occurs very rarely. Misenite is another more complex form of potassium bisulfate with the formula K8H6(SO4)7.
References
References
- (1895). "Principles and Practice of Agricultural Analysis: Fertilizers". Chemical Publishing Co..
- {{cite encyclopedia. H. Schultz. (2005). Wiley-VCH
- (2003). "Handbook of Inorganic Chemicals". McGraw-Hill.
- (1908). "Inorganic Chemistry: With the Elements of Physical and Theoretical Chemistry". John Wiley & Sons..
- (2006). "Chemical Compounds".
- Brauer, Georg. (1963). "Handbook of Preparative Inorganic Chemistry Vol. 1, 2nd Ed.". Academic Press.
- "Mercallite: Mineral information, data and localities".
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