Phosphoric acid: Difference between revisions
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<ref name=Bird>{{cite pub | <ref name=Bird>{{cite pub | ||
|title=POSITIVE IONS FROM NON METALLIC ELEMENTS|subtitle=A STUDY OF THE PRECIPITATION OF METALS FROM SOLUTIONS OF THEIR SALTS BY YELLOW PHOSPHORUS|year=1914|first1=R.M.|last1=Bird|first2=S.H.|last2=Diggs|publication=Journal of the American Chemical Society|volume=XXXVI|pages=1383|url=http://books.google.com/books?id=PCo1AQAAMAAJ&pg=PA1383#v=onepage&q&f=false}}</ref> | |title=POSITIVE IONS FROM NON METALLIC ELEMENTS|subtitle=A STUDY OF THE PRECIPITATION OF METALS FROM SOLUTIONS OF THEIR SALTS BY YELLOW PHOSPHORUS|year=1914|first1=R.M.|last1=Bird|first2=S.H.|last2=Diggs|publication=Journal of the American Chemical Society|volume=XXXVI|pages=1383|url=http://books.google.com/books?id=PCo1AQAAMAAJ&pg=PA1383#v=onepage&q&f=false}}</ref> | ||
Combine white [[phosphorus]] with a solution of [[copper sulfate]] | #Combine white [[phosphorus]] with a solution of [[copper sulfate]] | ||
: {{#Chem: 5 CuSO4 + 2P + 8H2O --> 5Cu+5H2SO4+2H3PO4}} | #: {{#Chem: 5 CuSO4 + 2P + 8H2O --> 5Cu+5H2SO4+2H3PO4}} | ||
===Extraction=== | ===Extraction=== | ||
====From apatite==== | ====From apatite==== | ||
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Phosphoric acid is synthesized by treating [[bone black]] with [[sulfuric acid]], producing phosphoric acid, and calcium sulfate (dihydrate) | Phosphoric acid is synthesized by treating [[bone black]] with [[sulfuric acid]], producing phosphoric acid, and calcium sulfate (dihydrate) | ||
:{{#Chem: Ca3(PO4)2+3H2SO4+6H2O-->2H3PO4+3CaSO4*2H2O}} | :{{#Chem: Ca3(PO4)2+3H2SO4+6H2O-->2H3PO4+3CaSO4*2H2O}} | ||
==Purification== | ==Purification== | ||
Much like '''sulfur trioxide''' can be introduced into dilute [[sulfuric acid]] to concentrate it, burnt [[phosphorus]] introduced into dilute phosphoric acid produces more concentrated phosphoric acid. | Much like '''sulfur trioxide''' can be introduced into dilute [[sulfuric acid]] to concentrate it, burnt [[phosphorus]] introduced into dilute phosphoric acid produces more concentrated phosphoric acid. | ||
Revision as of 00:58, 10 May 2023
| Chemical formula | H3PO4 |
|---|---|
| OTP appearance | white solid |
| Index of refraction | 1.4320 (85% aq. soln, 25°C) |
| Molar Mass(g/mol) | 97.995 |
| Melting Point(°C) | 42.35 |
| Boiling Point(°C) | 158 (decomp) |
| Solubility in water(g/L) | 3922 |
| Solubility in ethanol(g/L) | misc |
| NFPA 704 |  0
3
0
|
| Thermal Decomposition | Phosphoric acid
158°C H2O + HPO3 |
Uses
Primary
- Industrial chemical (early accessible mineral acid)
- Fertilizer
Secondary
- Can be used to produce hydrochloric and nitric acids.
- H3PO4 + 3 NaCl{Na3PO4 + 3 HCl(g) // Escaping HCl vapors keep reaction moving to the right110°C}→
- H3PO4 + 3 NaNO3{Na3PO4 + 3 HNO3(g) // Escaping HNO3 vapors keep reaction moving to the right120.5°C}→
- H3PO4 + 3 NaCl
Natural Occurrence
- Phosphoric does not occur naturally in quantity. If generated (by volcano, lightening, etc) it rapidly reacts with nearby materials and becomes phosphate.
Hazards
Character
- 85% phosphoric acid has a density of approximately 1.65g/cc
Production
Synthesis
From phosphorus
- Burn phosphorus, producing phosphorus pentoxide
- P4 + 5 O2 → 2 P2O5
- Dissolve phosphorus pentoxide in water producing phosphoric acid
- 3 H2O + P2O5 → 2 H3PO4
From copper sulfate
Combine phosphorus with a copper sulfate solution leaving sulfuric and phosphoric acid along with metallic copper. [1]
- Combine white phosphorus with a solution of copper sulfate
- 5 CuSO4 + 2 P + 8 H2O → 5 Cu + 5 H2SO4 + 2 H3PO4
Extraction
From apatite
Phosphoric acid is synthesized by treating apatite (mostly calcium triphosphate) with sulfuric acid, producing phosphoric acid, water, and gypsum.
- Ca5(PO4)3X + 5 H2SO4 + 10 H2O → 3 H3PO4 + 5CaSO4•2H2O + HX where X ∈ {OH, F, Cl, Br}
Thus if fluorapatite is used, hydrofluoric acid will be produced in recoverable amounts.
From bone black
Phosphoric acid is synthesized by treating bone black with sulfuric acid, producing phosphoric acid, and calcium sulfate (dihydrate)
- Ca3(PO4)2 + 3 H2SO4 + 6 H2O → 2 H3PO4 + 3CaSO4•2H2O
Purification
Much like sulfur trioxide can be introduced into dilute sulfuric acid to concentrate it, burnt phosphorus introduced into dilute phosphoric acid produces more concentrated phosphoric acid.
- 3 H2O + P2O5 → 2 H3PO4 (Catalyzed by existing phosphoric acid)
Testing
Storage
Disposal
See Also
- Mineral acid interconversion
- Vogel, A. (1836) "Ueber die Reduction der Quecksilbersalze durch Kupfer.".
J. Prakt. Chem. 8(1); pp107–109.
DOI:10.1002/prac.18360080118 - Straub, Walther (1903) "Phosphorus, reactions between copper and yellow"
Journal of the Chemical Society 84(2) Gurney & Jackson
References
- ↑ Bird, R.M.; Diggs, S.H. (1914) "POSITIVE IONS FROM NON METALLIC ELEMENTS"
Journal of the American Chemical Society XXXVI; pp1383.