“Iodic acid”的意思、由来-开放百科全书

词条

Iodic acid

释义

Preparation
Properties
Uses
Use in salt industry
References

{{Chembox
| Watchedfields = changed
| verifiedrevid = 470453970
| Name = Iodic acid
| ImageFile = Iodic-acid-2D.png
| ImageName = Iodic acid
| ImageFileL1 = Iodic-acid-3D-balls.png
| ImageNameL1 = Ball-and-stick model of iodic acid
| ImageFileR1 = Iodic-acid-3D-vdW.png
| ImageNameR1 = Space-filling model of iodic acid
| OtherNames = Iodic(V) acid
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 22761
| PubChem = 24345
| InChI = 1/HIO3/c2-1(3)4/h(H,2,3,4)
| InChIKey = ICIWUVCWSCSTAQ-UHFFFAOYAT
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 24857
| SMILES = O[I+2]([O-])[O-]
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 1161636
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/HIO3/c2-1(3)4/h(H,2,3,4)
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = ICIWUVCWSCSTAQ-UHFFFAOYSA-N
| CASNo = 7782-68-5
| CASNo_Ref = {{cascite|correct|CAS}}
|Section2={{Chembox Properties
| Formula = HIO₃
| MolarMass = 175.91 g/mol
| Appearance = White solid
| Density = 4.62 g/cm³, solid
| Solubility = 269 g/100 mL (20 °C)
| MeltingPtC = 110
| BoilingPt =
| ConjugateBase = Iodate
| pKa = 0.75
| MagSus = −48.0·10⁻⁶ cm³/mol
|Section3={{Chembox Structure
| MolShape =
| Dipole =
|Section7={{Chembox Hazards
| MainHazards = acid, corrosive, oxidant
| NFPA-H = 3
| NFPA-F = 0
| NFPA-R = 1
| NFPA-S = OX
| ExternalSDS =
| FlashPt = Non-flammable
|Section8={{Chembox Related
| OtherAnions =
| OtherCations = Lithium iodate
Potassium iodate
| OtherFunction = Chloric acid
Bromic acid
| OtherFunction_label = halogen oxoacids
| OtherCompounds = Hydroiodic acid
Iodine pentoxide
Periodic acid
}}

Iodic acid, HIO₃, can be obtained as a white or off-white solid. It dissolves in water very well, but it also exists in the pure state, as opposed to chloric acid or bromic acid. Iodic acid contains iodine in the oxidation state +5 and is one of the most stable oxo-acids of the halogens in its pure state. When iodic acid is carefully heated, it dehydrates to iodine pentoxide. On subsequent heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine.

Preparation

Iodic acid can be produced by oxidizing iodine I₂ with strong oxidizers such as nitric acid {{chem|HNO|3}}, chlorine {{chem|Cl|2}}, chloric acid {{chem|HClO|3}} or hydrogen peroxide {{chem|H|2|O|2}},^[1] for example:

{{chem|I|2}} + 6 {{chem|H|2|O}} + 5 {{chem|Cl|2}} {{eqm}} 2 {{chem|HIO|3}} + 10 HCl

Properties

Iodic acid is a relatively strong acid with a pK_a of 0.75. It is strongly oxidizing in acidic solution, less so in basic solution. When iodic acid acts as oxidizer, then the product of the reaction is either iodine, or iodide ion. Under some special conditions (very low pH and high concentration of chloride ions, such as in concentrated hydrochloric acid), iodic acid is reduced to iodine trichloride, a golden yellow compound in solution and no further reduction occurs. In the absence of chloride ions, when there is an excess amount of reductant, then all iodate is converted to iodide ion. When there is an excess amount of iodate, then part of the iodate is converted to iodine. It may be used in preparation of ionization to form alkyl halides.

Uses

Iodic acid is used as a strong acid in analytical chemistry. It may be used to standardize solutions of both weak and strong bases, using methyl red or methyl orange as the indicator.

Use in salt industry

Iodic acid can be used to synthesize sodium or potassium iodate for increasing iodine content of salt.{{Citation needed|date=June 2010}}

References

1. ^{{cite book|first1=Arnold F.|last1=Holleman|first2=Nils|last2=Wiberg|date=2007|title=Lehrbuch der Anorganischen Chemie|edition=102nd|language=German|location=Berlin|isbn=978-3-11-017770-1}}

随便看

开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。