Phosphoric acid: Difference between revisions
Jump to navigation
Jump to search
Line 32: | Line 32: | ||
:{{#Chem: Ca5(PO4)3X+5H2SO4+10H2O --> 3H3PO4+5CaSO4*2H2O+HX}} where X ∈ {OH, F, Cl, Br} | :{{#Chem: Ca5(PO4)3X+5H2SO4+10H2O --> 3H3PO4+5CaSO4*2H2O+HX}} where X ∈ {OH, F, Cl, Br} | ||
Thus if fluorapatite is used, '''hydrofluoric acid''' will be produced in recoverable amounts. | Thus if fluorapatite is used, '''hydrofluoric acid''' will be produced in recoverable amounts. | ||
====From bone black==== | ====From bone black==== | ||
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) |
Latest revision as of 22:24, 19 March 2025
Chemical formula | {{#Chem: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 |
|
Thermal Decomposition | Phosphoric acid
158°C {{#Chem: H2O + HPO3}} |
Uses
Primary
- Industrial chemical (early accessible mineral acid)
- Fertilizer
Secondary
- Can be used to produce hydrochloric and nitric acids.
- {{#Chem: H3PO4 + 3NaCl { = 110°C } Na3PO4 + 3HCl(g) // Escaping HCl vapors keep reaction moving to the right}}
- {{#Chem: H3PO4 + 3NaNO3 { = 120.5°C } Na3PO4 + 3 HNO3(g) // Escaping HNO3 vapors keep reaction moving to the right}}
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
- {{#Chem: P4 + 5O2 --> 2P2O5 }}
- Dissolve phosphorus pentoxide in water producing phosphoric acid
- {{#Chem: 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
- {{#Chem: 5 CuSO4 + 2P + 8H2O --> 5Cu+5H2SO4+2H3PO4}}
Extraction
From apatite
Phosphoric acid is synthesized by treating apatite (mostly calcium triphosphate) with sulfuric acid, producing phosphoric acid, water, and gypsum.
- {{#Chem: Ca5(PO4)3X+5H2SO4+10H2O --> 3H3PO4+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)
- {{#Chem: Ca3(PO4)2+3H2SO4+6H2O-->2H3PO4+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.
- {{#Chem: 3H2O + P2O5 --> 2H3PO4}} (Catalyzed by existing phosphoric acid)
Testing
Storage
Disposal
See Also
- Mineral acid intraconversion
- 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.