Sodium pyrosulfate
Appearance
(Redirected from Na2S2O7)
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IUPAC name
Disodium disulfate
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Other names
Sodium pyrosulphate; Disulfuric acid disodium salt, disodium disulfate; Sodium metabisulfate
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Identifiers | |
3D model (JSmol)
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ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.034.190 |
EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
Na2S2O7 | |
Molar mass | 222.12 g/mol |
Appearance | Translucent white crystals |
Density | 2.658 g/cm3 |
Melting point | 400.9 °C (753.6 °F; 674.0 K) |
Boiling point | decomposes at 460 °C (860 °F; 733 K) |
hydrolyses[2] | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium pyrosulfate is an inorganic compound with the chemical formula of Na2S2O7.[1] It is a colorless salt.[3] It hydrolyses in water to form sodium bisulfate with a chemical formula of NaHSO4 which has a pH of around 1.
Preparation
[edit]Sodium pyrosulfate is obtained by heating sodium bisulfate to 280 °C (536 °F) [4][5]
- 2 NaHSO4 → Na2S2O7 + H2O
Temperatures above 460 °C further decompose the compound, producing sodium sulfate and sulfur trioxide:
- Na2S2O7 → Na2SO4 + SO3
Applications
[edit]Sodium pyrosulfate was used in analytical chemistry. Samples are fused with sodium pyrosulfate to ensure complete dissolution before a quantitative analysis.[6][7]
See also
[edit]References
[edit]- ^ a b Olsen, J. C., ed. (1934). Van Nostrand's Chemical Annual. London: Chapman and Hall.
- ^ Heinz K. Hofmeister; John R. Van Wazer (1962). "Hydrolysis of Sodium Pyrosulfate". Inorganic Chemistry. 1 (4). ACS: 811–812. doi:10.1021/ic50004a019.
- ^ Helmold Plessen (2000). "Sodium Sulfates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_355. ISBN 978-3527306732.
- ^ Noyes, William (1913). A Textbook of Chemistry. New York: Henry Holt and Company. p. 186. Retrieved 13 January 2016.
- ^ von Plessen, Helmold (2000). "Sodium Sulfates". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a24_355. ISBN 9783527303854.
- ^ Nemodruk, Aleksandr; Karalova, Zinaida (1969). Analytical chemistry of boron: Analytical chemistry of the elements. Charlottesville, VA: Ann Arbor-Humphrey Science Publishers. pp. 23 & 193. ISBN 9780250399192.
- ^ Kiely, P. V.; Jackson, M. L. (1965). "Quartz, Feldspar, and Mica Determination for Soils by Sodium Pyrosulfate Fusion". Soil Science Society of America Journal. 29 (2): 159–163. Bibcode:1965SSASJ..29..159K. doi:10.2136/sssaj1965.03615995002900020015x.