Difference between revisions of "Iodic acid"
Physchim62 (talk | contribs) (Created page with ''''Iodic acid''', HIO<sub>3</sub>, is a moderately strong oxoacid of iodine. It forms a series of salts called iodates. ==Notes and references== ===Notes=== {{reflis…') |
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+ | {{Chembox | ||
+ | | IUPACName = iodic acid | ||
+ | | Section1 = {{Chembox Identifiers | ||
+ | | CASNo = 7782-68-5 | ||
+ | | CASNo_Ref = {{cascite}} | ||
+ | | EINECS = 231-962-1 | ||
+ | | ChemSpiderID = 22761 | ||
+ | | InChI = InChI=1S/HIO3/c2-1(3)4/h(H,2,3,4) | ||
+ | | StdInChI=1S/HIO3/c2-1(3)4/h(H,2,3,4) | ||
+ | | InChIKey = ICIWUVCWSCSTAQ-UHFFFAOYAT | ||
+ | | StdInChIKey = ICIWUVCWSCSTAQ-UHFFFAOYSA-N | ||
+ | }} | ||
+ | | Section2 = {{Chembox Properties | ||
+ | | Reference = <ref name="G&E">{{Greenwood&Earnshaw1st|page=1010}}.</ref><ref>{{RubberBible62nd|page=B-106}}.</ref> | ||
+ | | Formula = HIO<sub>3</sub> | ||
+ | | MolarMass = 175.91 g mol<sup>−1</sup> | ||
+ | | Appearance = white crystals | ||
+ | | Density = 4.629 g cm<sup>−3</sup> | ||
+ | | MeltingPt = 100 °C ''decomp.'' | ||
+ | | Solubility = 286 g/100 ml (0 °C)<br/>473 g/100 ml (80 °C) | ||
+ | | SolubleOther = | ||
+ | | Solvent = | ||
+ | | pKa = 0.804 | ||
+ | }} | ||
+ | | Section3 = {{Chembox Structure | ||
+ | | Reference = <ref name="G&E"/> | ||
+ | | MolShape = pyramidal; ''r''(I=O) = 181 pm, ''r''(I–OH) = 189 pm, O=I=O = 101.4°, O=I–OH = 97° | ||
+ | }} | ||
+ | | Section7 = {{Chembox Hazards | ||
+ | | Reference = <ref>{{GHS class NZ|id=12620|accessdate=2010-09-09}}.</ref> | ||
+ | | ExternalMSDS = | ||
+ | | EUIndex = not listed | ||
+ | | GHSPictograms = {{GHS03|Ox. Sol. 2}}{{GHS05|Skin Corr. 1C, Eye Dam. 1}} | ||
+ | | GHSSignalWord = DANGER | ||
+ | | HPhrases = {{H-phrases|272|314|318}} | ||
+ | | PPhrases = {{P-phrases|210|220|221|260|264|280| 301+330+331|303+361+353|363|304+340|310|321|305+351+338|370+378|405|501}} | ||
+ | | FlashPt = non-flammable | ||
+ | }} | ||
+ | | Section8 = {{Chembox Related | ||
+ | | OtherCpds = [[Hydroiodic acid]]<br/>[[Hypoiodous acid]]<br/>[[Periodic acid]] | ||
+ | | OtherFunctn = [[Chloric acid]]<br/>[[Bromic acid]] | ||
+ | | Function = halic acids | ||
+ | }} | ||
+ | }} | ||
'''Iodic acid''', HIO<sub>3</sub>, is a moderately strong [[oxoacid]] of [[iodine]]. It forms a series of salts called [[iodate]]s. | '''Iodic acid''', HIO<sub>3</sub>, is a moderately strong [[oxoacid]] of [[iodine]]. It forms a series of salts called [[iodate]]s. | ||
+ | |||
+ | Iodic acid may be prepared by the oxidation of suspensions of iodine in water, either by [[electrolysis]] or with [[nitric acid]].<ref name="G&E"/> Unlike [[Chloric acid|chloric]] and [[bromic acid]]s, it can be isolated as a white crystalline air-stable solid. The solid decomposes on heating, first to [[anhydro-iodic acid]], HIO<sub>3</sub>·I<sub>2</sub>O<sub>5</sub> or HI<sub>3</sub>O<sub>8</sub>, at about 100 °C, then to [[iodine pentoxide]] at about 200 °C.<ref name="G&E"/> | ||
+ | |||
+ | Iodic acid is used as [[primary standard]] [[strong acid]] in [[acid–base titration]]s because it can be weighed as a pure solid and has a relatively high [[molar mass]]. However, the solid cannot be dried in a 110 °C oven because of dehydration, and recrystallization is difficult because of the high solubility of HIO<sub>3</sub>: for these reasons, [[potassium biiodate]] is usually preferred as a strong-acid standard. | ||
==Notes and references== | ==Notes and references== | ||
Line 14: | Line 62: | ||
[[Category:Iodates|*]] | [[Category:Iodates|*]] | ||
[[Category:Acids]] | [[Category:Acids]] | ||
+ | [[Category:Acid–base titrations]] | ||
{{CC-BY-3.0}} | {{CC-BY-3.0}} |
Latest revision as of 12:11, 1 January 2011
Iodic acid | |
---|---|
IUPAC name | iodic acid |
Identifiers | |
InChI | InChI=InChI=1S/HIO3/c2-1(3)4/h(H,2,3,4) |
InChIKey | ICIWUVCWSCSTAQ-UHFFFAOYAT |
Standard InChI | InChI=1S/HIO3/c2-1(3)4/h(H,2,3,4) |
Standard InChIKey | ICIWUVCWSCSTAQ-UHFFFAOYSA-N |
CAS number | [ ] |
EC number | |
ChemSpider | |
Properties[1][2] | |
Chemical formula | HIO3 |
Molar mass | 175.91 g mol−1 |
Appearance | white crystals |
Density | 4.629 g cm−3 |
Melting point |
100 °C decomp. |
Solubility in water | 286 g/100 ml (0 °C) 473 g/100 ml (80 °C) |
Acidity (pKa) | 0.804 |
Structure[1] | |
Molecular geometry | pyramidal; r(I=O) = 181 pm, r(I–OH) = 189 pm, O=I=O = 101.4°, O=I–OH = 97° |
Hazards[3] | |
EU index number | not listed |
GHS pictograms | |
GHS signal word | DANGER |
GHS hazard statements | H272, H314, H318 |
GHS precautionary statements | P210, P220, P221, P260, P264, P280, P301+330+331, P303+361+353, P363, P304+340, P310, P321, P305+351+338, P370+378 |
Flash point | non-flammable |
Related compounds | |
Other halic acids | Chloric acid Bromic acid |
Other compounds | Hydroiodic acid Hypoiodous acid Periodic acid |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
Iodic acid, HIO3, is a moderately strong oxoacid of iodine. It forms a series of salts called iodates.
Iodic acid may be prepared by the oxidation of suspensions of iodine in water, either by electrolysis or with nitric acid.[1] Unlike chloric and bromic acids, it can be isolated as a white crystalline air-stable solid. The solid decomposes on heating, first to anhydro-iodic acid, HIO3·I2O5 or HI3O8, at about 100 °C, then to iodine pentoxide at about 200 °C.[1]
Iodic acid is used as primary standard strong acid in acid–base titrations because it can be weighed as a pure solid and has a relatively high molar mass. However, the solid cannot be dried in a 110 °C oven because of dehydration, and recrystallization is difficult because of the high solubility of HIO3: for these reasons, potassium biiodate is usually preferred as a strong-acid standard.
Notes and references
Notes
References
- ↑ 1.0 1.1 1.2 1.3 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; p 1010. ISBN 0-08-022057-6.
- ↑ CRC Handbook of Chemistry and Physics, 62nd ed.; Weast, Robert C., Ed.; CRC Press: Boca Raton, FL, 1981; p B-106. ISBN 0-8493-0462-8.
- ↑ HSNO Chemical Classification Information Database, <http://www.ermanz.govt.nz/Chemicals/ChemicalDisplay.aspx?SubstanceID=12620> (accessed 9 September 2010), New Zealand Environmental Risk Management Authority.
External links
See also the corresponding article on Wikipedia. |
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