What is Tellurous acid?
{{redirect|Tellurium acid|the acid made of tellurate ions|Telluric acid|the acid made of telluride ions|Hydrogen telluride}} {{chembox |Name = Tellurous acid| ImageFile =Tellurige_Säure.svg | ImageName =Tellurous Acid | ImageSize = |IUPACName = Tellurous acid|OtherNames = Tellurium dioxide hydrate, tellurium(IV) oxide hydrate|Section1 = {{Chembox Identifiers | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 30465 | SMILES = O=[Te](O)O | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 23310 | PubChem = 24936 | InChI = 1/H2O3Te/c1-4(2)3/h(H2,1,2,3) | InChIKey = SITVSCPRJNYAGV-UHFFFAOYAI | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/H2O3Te/c1-4(2)3/h(H2,1,2,3) | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = SITVSCPRJNYAGV-UHFFFAOYSA-N | CASNo_Ref = {{cascite|changed|??}} | CASNo = 10049-23-7 }}|Section2 = {{Chembox Properties | Formula = H<sub>2</sub>TeO<sub>3</sub> | MolarMass = 177.616 grams | Appearance = colorless crystals | Density = ~ 3 g/cm<sup>3</sup> | Solubility = negligible | MeltingPt = | BoilingPt = decomp. | pKa = p''K''<sub>a</sub>(1) = 2.48, p''K''<sub>a</sub>(2) = 7.70 | pKb = | Viscosity = }}|Section3 = {{Chembox Structure | MolShape = pyramidal at Te | Coordination = | CrystalStruct = unknown | Dipole = }}|Section7 = {{Chembox Hazards | ExternalMSDS = | MainHazards = | FlashPt = | RPhrases = | SPhrases = }}|Section8 = {{Chembox Related | OtherAnions = [[Selenous acid]]<br>[[Sulfurous acid]] | OtherCations = [[Sodium tellurite]] | OtherCpds = [[Telluric acid]] <br> [[Selenic acid]] <br> [[Sulfuric acid]] }} }} '''Tellurous acid''' is a [[chemical compound]]. It is also an [[acid]]. Its chemical formula is H<sub>2</sub>TeO<sub>3</sub>. It contains [[hydrogen]] and [[tellurite]] [[ion]]s. It can be made by reacting [[tellurium dioxide]] with water. It is not made as easily as [[telluric acid]]. It is a weak [[oxidizing agent]] and a weak [[reducing agent]]. It