Ka Value Of Phosphoric Acid

Chemical chemical compound (PO(OH)3)

This article is about orthophosphoric acrid. For other acids commonly called "phosphoric acid", see Phosphoric acids and phosphates.

Phosphoric acid

Names
IUPAC name Phosphoric acrid
Other names Orthophosphoric acid
Identifiers
CAS Number	7664-38-ii Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:26078 Y
ChEMBL	ChEMBL1187 Y
ChemSpider	979 Y
ECHA InfoCard	100.028.758
EC Number	231-633-two
E number	E338 (antioxidants, ...)
KEGG	D05467 Y
PubChem CID	1004
RTECS number	TB6300000
UNII	E4GA8884NN Y
UN number	1805
CompTox Dashboard (EPA)	DTXSID5024263
InChI InChI=1S/H3O4P/c1-5(two,3)4/h(H3,1,two,3,4) Y Cardinal: NBIIXXVUZAFLBC-UHFFFAOYSA-N Y InChI=1/H3O4P/c1-5(2,3)4/h(H3,1,2,3,4) Cardinal: NBIIXXVUZAFLBC-UHFFFAOYAI
SMILES OP(=O)(O)O
Properties
Chemical formula	H3POiv
Molar mass	97.994 g·mol−1
Advent	Colorless solid
Odor	Odorless
Density	1.6845 g/cm3 (25 °C, 85%),[one] 1.834 g/cm3 (solid)[two]
Melting point	xl–42.four °C (104.0–108.iii °F; 313.1–315.5 K)[six]
Boiling point	212 °C (414 °F)[3](merely h2o evaporates)[4]
Solubility in water	392.ii chiliad/(100 thou) (−16.iii °C) 369.4g/(100 mL) (0.five °C) 446 g/(100 mL) (15 °C)[5] 548g/(100 mL) (twenty °C)[6]
Solubility	Soluble in ethanol
log P	−2.15[vii]
Vapor force per unit area	0.03mmHg (twenty°C)[8]
Conjugate base of operations	Dihydrogen phosphate
Magnetic susceptibility (χ)	−43.8·10−six cm3/mol[10]
Refractive alphabetize (n D)	ane.3420 (viii.8% due west/w aq. soln.)[xi] 1.4320 (85% aq. soln) 25 °C
Viscosity	two.4–9.fourcP (85% aq. soln.) 147 cP (100%)
Structure
Crystal structure	Monoclinic
Molecular shape	Tetrahedral
Thermochemistry[12]
Estrus capacity (C)	145.0 J/(mol⋅K)
Std molar entropy (S ⦵ 298)	150.8 J/(mol⋅Thou)
Std enthalpy of germination (Δf H ⦵ 298)	−1271.seven kJ/mol
Gibbs complimentary free energy (Δf Thou ⦵)	−1123.vi kJ/mol
Hazards
GHS labelling:
Pictograms	[13]
Signal word	Danger
Hazard statements	H290, H314 [13]
Precautionary statements	P280, P305+P351+P338, P310 [13]
NFPA 704 (burn diamond)	3 0 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	1530 mg/kg (rat, oral)[14]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA ane mg/chiliadthree [viii]
REL (Recommended)	TWA 1 mg/m3 ST 3 mg/mthree [8]
IDLH (Firsthand danger)	1000 mg/1000three [viii]
Condom data sheet (SDS)	ICSC 1008
Related compounds
Related phosphorus oxoacids	Hypophosphorous acid Phosphorous acid Pyrophosphoric acrid Triphosphoric acid Peroxomonophosphoric acid Peroxodiphosphoric acrid
Except where otherwise noted, data are given for materials in their standard land (at 25 °C [77 °F], 100 kPa). Nverify (what is Y Northward  ?) Infobox references

Chemical compound

Phosphoric acrid (orthophosphoric acid, monophosphoric acrid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula H₃PO₄ . Information technology is commonly encountered as an 85% aqueous solution, which is a colourless, odourless, and non-volatile syrupy liquid. It is a major industrial chemical, being a component of many fertilizers.

The chemical compound is an acid. Removal of all three H⁺ ions gives the phosphate ion PO 3− 4 . Removal of one or two protons gives dihydrogen phosphate ion H₂PO − four , and the hydrogen phosphate ion HPO two− 4 , respectively. Phosphoric acrid forms esters, called organophosphates.^[15]

The name "orthophosphoric acid" can be used to distinguish this specific acrid from other "phosphoric acids", such as pyrophosphoric acrid. All the same, the term "phosphoric acid" oft ways this specific compound; and that is the electric current IUPAC nomenclature.

Production [edit]

Phosphoric acid is produced industrially by one of ii routes, wet processes and dry.^[16]

Wet process [edit]

In the moisture process, a phosphate-containing mineral such equally calcium hydroxyapatite and fluorapatite are treated with sulfuric acid.^[17]

Ca₅(PO₄)₃OH + 5 H₂SO₄ → 3 H₃PO₄ + 5 CaSO₄ + H₂O

Ca_v(PO_four)_threeF + v H₂SO₄ → 3 H₃PO_four + 5 CaSO₄ + HF

Calcium sulfate (gypsum, CaSO₄ ) is a by-product, which is removed as phosphogypsum. The hydrogen fluoride (HF) gas is streamed into a wet (h2o) scrubber producing hydrofluoric acid. In both cases the phosphoric acrid solution ordinarily contains 23–33% P2O5 (32–46% H_threePO₄ ). Information technology may be concentrated to produce commercial- or merchant-grade phosphoric acrid, which contains about 54–62% P_twoO₅ (75–85% H₃PO₄ ). Farther removal of water yields superphosphoric acrid with a P₂O₅ concentration above 70% (respective to about 100% H₃PO_iv ). The phosphoric acid from both processes may exist further purified by removing compounds of arsenic and other potentially toxic impurities.

Dry process [edit]

To produce food-grade phosphoric acid, phosphate ore is commencement reduced with coke in an electrical arc furnace, to give elemental phosphorus. Silica is also added, resulting in the product of calcium silicate slag. Elemental phosphorus is distilled out of the furnace and burned with air to produce loftier-purity phosphorus pentoxide, which is dissolved in water to make phosphoric acid.^[18]

Acidic properties [edit]

In aqueous solution phosphoric acrid behaves equally a triprotic acid.

H₃PO_four ⇌ H₂PO − 4 + H⁺ , pK _a1 = 2.fourteen

H₂PO − iv ⇌ HPO ii− 4 + H⁺ , pGrand _a2 = 7.20

HPO 2− 4 ⇌ PO 3− four + H⁺ , p1000 _a3 = 12.37

The divergence between successive pK _a values is sufficiently big so that salts of either monohydrogen phosphate, HPO 2− iv or dihydrogen phosphate, H_twoPO − 4 , tin be prepared from a solution of phosphoric acrid by adjusting the pH to be mid-way betwixt the corresponding pK values.

Uses [edit]

The dominant utilize of phosphoric acrid is for fertilizers, consuming approximately 90% of production.^[19]

Application	Demand (2006) in thousands of tons	Main phosphate derivatives
Soaps and detergents	1836	STPP
Nutrient industry	309	STPP (NavP3Oten ), SHMP, TSP, SAPP, SAlP, MCP, DSP (NatwoHPO4 ), H3POfour
Water treatment	164	SHMP, STPP, TSPP, MSP (NaH2PO4 ), DSP
Toothpastes	68	DCP (CaHPO4 ), IMP, SMFP
Other applications	287	STPP (Na3PthreeO9 ), TCP, APP, DAP, zinc phosphate (Zn3(PO4)2 ), aluminium phosphate (AlPO4 ), HiiiPOiv

Food-grade phosphoric acid (additive E338^[20]) is used to acidify foods and beverages such as various colas and jams, providing a tangy or sour gustatory modality. The phosphoric acid also serves equally a preservative.^[21] Soft drinks containing phosphoric acid, which would include Coca-Cola, are sometimes called phosphate sodas or phosphates. Phosphoric acid in soft drinks has the potential to crusade dental erosion.^[22] Phosphoric acid as well has the potential to contribute to the formation of kidney stones, particularly in those who take had kidney stones previously.^[23]

Specific applications of phosphoric acid include:

• in anti-rust handling by phosphate conversion coating or passivation
• to foreclose iron oxidation by means of the Parkerization process
• every bit an external standard for phosphorus-31 nuclear magnetic resonance
• in phosphoric acid fuel cells
• in activated carbon production^[24]
• in compound semiconductor processing, to etch Indium gallium arsenide selectively with respect to indium phosphide^[25]
• in microfabrication to etch silicon nitride selectively with respect to silicon dioxide^[26]
• equally a pH adjuster in cosmetics and skin-care products^[27]
• equally a sanitizing agent in the dairy, food, and brewing industries^[28]

Safety [edit]

Phosphoric acid is not a strong acid. However, at moderate concentrations phosphoric acid solutions are irritating to the skin. Contact with concentrated solutions can cause severe skin burns and permanent eye impairment.^[29]

A link has been shown between long-term regular cola intake and osteoporosis in after middle age in women (but non men).^[thirty]

Come across also [edit]

• Phosphate fertilizers, such equally ammonium phosphate fertilizers

References [edit]

1. ^ Christensen, J. H.; Reed, R. B. (1955). "Design and Analysis Data—Density of Aqueous Solutions of Phosphoric Acid Measurements at 25 °C". Ind. Eng. Chem. 47 (vi): 1277–1280. doi:10.1021/ie50546a061.
2. ^ "CAMEO Chemicals Datasheet – Phosphoric Acrid". Archived from the original on 15 August 2019. Retrieved 15 August 2019.
3. ^ "Phosphoric acid". world wide web.chemspider.com. Archived from the original on 12 March 2020. Retrieved 3 March 2020.
4. ^ Brown, Earl H.; Whitt, Carlton D. (1952). "Vapor Pressure of Phosphoric Acids". Industrial & Technology Chemical science. 44 (3): 615–618. doi:10.1021/ie50507a050.
5. ^ Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand. Archived from the original on 11 March 2020. Retrieved 2 June 2014.
6. ^ ^{a b} Haynes, p. 4.80
7. ^ "phosphoric acid_msds". Archived from the original on 4 July 2017. Retrieved 2 May 2018.
8. ^ ^{a b c d} NIOSH Pocket Guide to Chemical Hazards. "#0506". National Found for Occupational Condom and Health (NIOSH).
9. ^ Haynes, p. 5.92
10. ^ Haynes, p. 4.134
11. ^ Edwards, O. W.; Dunn, R. L.; Hatfield, J. D. (1964). "Refractive Index of Phosphoric Acid Solutions at 25 C.". J. Chem. Eng. Data. ix (iv): 508–509. doi:10.1021/je60023a010.
12. ^ Haynes, p. five.thirteen
13. ^ ^{a b c} Sigma-Aldrich Co., Phosphoric acrid.
14. ^ "Phosphoric acrid". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
15. ^ Westheimer, F.H. (6 June 1987). "Why nature chose phosphates". Scientific discipline. 235 (4793): 1173–1178 (see pp. 1175–1176). Bibcode:1987Sci...235.1173W. CiteSeerX10.1.1.462.3441. doi:10.1126/science.2434996. PMID 2434996.
16. ^ Becker, Pierre (1988). Phosphates and phosphoric acid. New York: Marcel Dekker. ISBN978-0824717124.
17. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 520–522. ISBN978-0-08-037941-8.
18. ^ Geeson, Michael B.; Cummins, Christopher C. (2020). "Let's Make White Phosphorus Obsolete". ACS Fundamental Science. 6 (six): 848–860. doi:x.1021/acscentsci.0c00332. PMC7318074. PMID 32607432.
19. ^ Schrödter, Klaus; Bettermann, Gerhard; Staffel, Thomas; Wahl, Friedrich; Klein, Thomas; Hofmann, Thomas (2008). "Phosphoric Acid and Phosphates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_465.pub3.
20. ^ "Current EU approved additives and their East Numbers". Foods Standards Agency. 14 March 2012. Archived from the original on 21 August 2013. Retrieved 22 July 2012.
21. ^ "Why is phosphoric acid used in some Coca‑Cola drinks?| Oftentimes Asked Questions | Coca-Cola GB". www.coca-cola.co.uk. Archived from the original on 2 Baronial 2021. Retrieved 31 August 2021.
22. ^ Moynihan, P. J. (23 November 2002). "Dietary advice in dental do". British Dental Journal. 193 (10): 563–568. doi:ten.1038/sj.bdj.4801628. PMID 12481178.
23. ^ Qaseem, A; Dallas, P; Forciea, MA; Starkey, G; et al. (4 November 2014). "Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults: A clinical practice guideline from the American College of Physicians". Annals of Internal Medicine. 161 (9): 659–67. doi:10.7326/M13-2908. PMID 25364887.
24. ^ Toles, C.; Rimmer, Due south.; Hower, J. C. (1996). "Product of activated carbons from a washington lignite using phosphoric acrid activation". Carbon. 34 (xi): 1419. doi:10.1016/S0008-6223(96)00093-0.
25. ^ Wet chemic carving. Archived 25 September 2012 at the Wayback Machine umd.edu.
26. ^ Wolf, South.; R. Northward. Tauber (1986). Silicon processing for the VLSI era: Volume i – Process technology. p. 534. ISBN978-0-9616721-6-4.
27. ^ "Ingredient dictionary: P". Cosmetic ingredient dictionary. Paula'southward Choice. Archived from the original on eighteen January 2008. Retrieved 16 November 2007.
28. ^ "STAR SAN" (PDF). Five Star Chemicals. Archived (PDF) from the original on 8 Feb 2016. Retrieved 17 Baronial 2015.
29. ^ "Phosphoric Acid, 85 wt.% SDS". Sigma-Aldrich. 5 May 2016. Archived from the original on 18 January 2017. Retrieved sixteen January 2017.
30. ^ Tucker KL, Morita 1000, Qiao N, Hannan MT, Cupples LA, Kiel DP (1 October 2006). "Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study". American Journal of Clinical Nutrition. 84 (4): 936–942. doi:10.1093/ajcn/84.4.936. PMID 17023723.

Cited sources [edit]

• Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). CRC Press. ISBN978-1439855119.

External links [edit]

• National pollutant inventory – Phosphoric acrid fact sheet
• NIOSH Pocket guide to chemic hazards

Ka Value Of Phosphoric Acid,

Source: https://en.wikipedia.org/wiki/Phosphoric_acid

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