Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Sulfurous acid: Difference between pages

{{short description|Chemical compound}}

{{distinguish|Sulfuric acid}}

| verifiedrevid = 470482579

| Name = Sulfurous acid

| ImageFile_Ref = {{chemboximage|correct|??}}

| ImageFile = Sulfurous-acid-2D-pyramidal.png

| ImageSize = 150px

| ImageName = Sulfuric(IV) acid

| ImageFile1 = Sulfurous-acid-3D-balls.png

| ImageName1 = Ball-and-stick model of sulfurous acid

| OtherNames = Sulfuric(IV) acid<br/>Thionic acid<br/>Sulfinic acid

| IUPACName = Sulfurous acid

| SystematicName =

| Section1 = {{Chembox Identifiers

| CASNo = 7782-99-2

| CASNo_Ref = {{cascite|correct|CAS}}

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 48854

| ChEMBL_Ref = {{ebicite|correct|EBI}}

| ChEMBL = 1161699

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| EC_number = 231-973-1

| Gmelin = 1458

| SMILES = O[S](=O)O

| SMILES1 = O[S+](O)[O-]

| SMILES1_Comment = Tautomer

| Section2 = {{Chembox Properties

| Formula = {{chem2|H2SO3}}

| MolarMass = 82.07 g/mol

| ConjugateBase = [[Bisulfite]]

| pKa = 1.857, 7.172<ref name=P82db>{{cite book|title=Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution|editor-first=D.&nbsp;D.|editor-last=Perrin|edition=2nd|series=[[IUPAC]] Chemical Data|issue=29|publisher=Pergamon|location=Oxford|year=1982|publication-date=1984|orig-date=1969|lccn=82-16524|isbn=0-08-029214-3|at=Entry&nbsp;217}}</ref>

| Section3 =

| Section4 =

| Section5 =

| Section6 =

| Section7 = {{Chembox Hazards

| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0074.htm ICSC 0074]

| GHSPictograms = {{GHS05}}{{GHS07}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|314|332}}

| PPhrases = {{P-phrases|260|261|264|271|280|301+330+331|303+361+353|304+312|304+340|305+351+338|310|312|321|363|405|501}}

| FlashPt = Non-flammable

| Section8 = {{Chembox Related

| OtherCompounds = [[Sulfur dioxide]]<br/>[[Sulfuric acid]]<br/>[[Selenous acid]]

'''Sulfuric(IV) acid''' ([[United Kingdom]] spelling: '''sulphuric(IV) acid'''), also known as '''sulfurous''' (UK:&nbsp;'''sulphurous''') '''acid''' and '''thionic acid''',{{citation needed|date=July 2023}} is the [[chemical compound]] with the [[chemical formula|formula]] {{chem2|H2SO3}}.

[[Raman spectroscopy|Raman spectra]] of solutions of [[sulfur dioxide]] in water show only signals due to the {{chem2|SO2}} molecule and the bisulfite ion, {{chem2|HSO3−}}.<ref>{{Jolly2nd}}</ref> The intensities of the signals are consistent with the following [[chemical equilibrium|equilibrium]]:

{{block indent|1={{chem2|SO2 + H2O ⇌ HSO3− + H+}}{{spaces|10}}''K''_a = 1.54{{e|−2}}; p''K''_a = 1.81.}}

¹⁷O [[NMR spectroscopy]] provided evidence that solutions of sulfurous acid and protonated sulfites contain a mixture of isomers, which is in equilibrium:<ref name="InorgChem">{{cite book

| title = Inorganic Chemistry, 3rd Edition

| chapter = Chapter 16: The group 16 elements

| author1 = Catherine E. Housecroft

| author2 = Alan G. Sharpe

| publisher = Pearson

| year = 2008

| isbn = 978-0-13-175553-6

| page = 520

}}</ref>

{{block indent|{{chem2|[H\sOSO2]− ⇌ [H\sSO3]−}}}}

Attempts to concentrate the solutions of sulfurous acid simply reverses the equilibrium, producing sulfur dioxide and water vapor. A [[clathrate]] with the formula {{chem2|4SO2*23H2O}} has been crystallised. It decomposes above 7&nbsp;°C.

==History and production==

Sulfurous acid is commonly known to not exist in its free state, and due to this, it is stated in textbooks that it cannot be isolated in the water-free form.<ref>{{Greenwood&Earnshaw2nd|page=719}}</ref> However, the molecule has been detected in the gas phase in 1988 by the dissociative ionization of [[diethyl sulfite]].<ref>{{cite journal |author1=D. Sülzle |author2=M. Verhoeven |author3=J. K. Terlouw |author4=H. Schwarz | title = Generation and Characterization of Sulfurous Acid (H₂SO₃) and of Its Radical Cation as Stable Species in the Gas Phase | journal = [[Angew. Chem. Int. Ed. Engl.]] | volume = 27 | pages = 1533–4 | year = 1988 | doi = 10.1002/anie.198815331 | issue = 11}}</ref> The conjugate bases of this elusive acid are, however, common anions, [[bisulfite]] (or hydrogen sulfite) and [[sulfite]]. Sulfurous acid is an intermediate species in the formation of [[acid rain]] from sulfur dioxide.<ref>{{cite book|last1=McQuarrie |last2= Rock |date=1987 |title=General Chemistry |edition=2nd |publisher=W.H. Freeman and Company |location=New York |page=243 |ISBN=0-7167-1806-5}}</ref>

==Uses==

Aqueous solutions of sulfur dioxide, which sometimes are referred to as sulfurous acid, are used as [[reducing agent]]s and as disinfectants, as are solutions of [[bisulfite]] and [[sulfite]] salts. They are [[oxidisation|oxidise]]d to [[sulfuric acid]] or [[sulfate]] by accepting another [[oxygen]] atom.<ref>L. Kolditz, ''Anorganische Chemie'', VEB Deutscher Verlag der Wissenschaften, Berlin 1983, S. 476.</ref>

==See also==

* [[Bisulfite]]

* [[Carbonic acid]]

* [[Pulp (paper)#History|Pulp (paper)]]

* [[Sulfite process|Sulfite paper pulp process]]

* [[Sulfite]]

* [[Sulfuric acid]]

==References==

{{reflist}}

{{Hydrogen compounds}}

{{Sulfites}}

{{Authority control}}

[[Category:Hydrogen compounds]]

[[Category:Sulfites]]

[[Category:Sulfur oxoacids]]