Phosphoric acid
IUPAC name	trihydroxidooxidophosphorus phosphoric acid
Other names	Orthophosphoric acid
Identifiers
CAS number	[7664-38-2]
Properties
Molecular formula	H3PO4
Molar mass	98. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 0 g/mol
Appearance	white solid or colourless, viscous liquid (>42°C)
Density	1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 685 g/ml (liquid)
Melting point	42. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 35 °C, 316 K, 108 °F
Boiling point	158 °C, 431 K, 316 °F (decomp. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid )
Acidity (pKa)	2. 12, 7. 21, 12. 67
Viscosity	85% aqueous solution  ? cP
Hazards
EU classification	Corrosive(C)
R-phrases	R34
S-phrases	(S1/2), S26, S45
Related compounds
Related Phosphorus acid	Hypophosphorous acid Phosphorous acid Pyrophosphoric acid Tripolyphosphoric acid Hypophosphoric acid Perphosphoric acid Permonophosphoric acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a mineral (inorganic) acid having the chemical formula H₃PO₄. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. The poise (symbol P pwɑːz is the unit of dynamic Viscosity in the Centimetre gram second system of units. Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws regulations and administrative provisions relating to the classification packaging and labelling R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. Phosphorous acid is the compound described by the formula H3PO3 Pyrophosphoric acid, also known under the name diphosphoric acid, is a syrupy liquid or a viscous off-white solid Triphosphoric acid, also tripolyphosphoric acid, with formula H5P3O10 is a condensed form of Phosphoric acid. In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly A mineral acid is an Acid derived by Chemical reaction from inorganic Minerals as opposed to Organic acids These have Hydrogen A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the By contrast, orthophosphoric acid molecules can combine with themselves to form a variety of compounds referred to as phosphoric acids in a more general way. In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are The term phosphoric acid can also refer to a chemical or reagent consisting of phosphoric acids, usually mostly orthophosphoric acid. A chemical substance is a Material with a definite chemical composition. A reagent or reactant is a substance or compound consumed during a Chemical reaction.

Orthophosphoric acid chemistry

Pure anhydrous phosphoric acid is a white solid that melts at 42. 35 °C to form a colorless, viscous liquid.

Most people and even chemists refer to orthophosphoric acid as phosphoric acid, which is the IUPAC name for this compound. The prefix ortho is used to distinguish the acid from other phosphoric acids, called polyphosphoric acids. Orthophosphoric acid is a non-toxic, inorganic, rather weak triprotic acid, which, when pure, is a solid at room temperature and pressure. Toxicity is the degree to which a substance is able to damage an exposed organism Traditionally inorganic compounds are considered to be of mineral not biological origin In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface The chemical structure of orthophosphoric acid is shown above in the data table. Chemical structure refers to Molecular geometry, Electronic structure and Crystal structure. Orthophosphoric acid is a very polar molecule; therefore it is highly soluble in water. "Polar molecule" and "Non-polar" redirect here In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by The oxidation state of phosphorus (P) in ortho- and other phosphoric acids is +5; the oxidation state of all the oxygen atoms (O) is -2 and all the hydrogen atoms (H) is +1. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Triprotic means that an orthophosphoric acid molecule can dissociate up to three times, giving up an H⁺ each time, which typically combines with a water molecule, H₂O, as shown in these reactions:

H₃PO_4(s)   + H₂O_(l) ⇌ H₃O⁺_(aq) + H₂PO₄^–_(aq)       K_a1= 7. Water ( H2[[oxygen O]] H OH) is the most abundant Molecule on Earth 's surface composing of about 70% of the Earth's surface as A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called 5×10⁻³

H₂PO₄^–_(aq)+ H₂O_(l) ⇌ H₃O⁺_(aq) + HPO₄^2–_(aq)       K_a2= 6. 2×10⁻⁸

HPO₄^2–_(aq)+ H₂O_(l) ⇌ H₃O⁺_(aq) +  PO₄^3–_(aq)        K_a3= 2. 14×10⁻¹³

The anion after the first dissociation, H₂PO₄^–, is the dihydrogen phosphate anion. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge The anion after the second dissociation, HPO₄^2–, is the hydrogen phosphate anion. The anion after the third dissociation, PO₄^3–, is the phosphate or orthophosphate anion. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. For each of the dissociation reactions shown above, there is a separate acid dissociation constant, called K_a1, K_a2, and K_a3 given at 25°C. Associated with these three dissociation constants are corresponding pK_a1=2. 12 , pK_a2=7. 21 , and pK_a3=12. 67 values at 25°C. Even though all three hydrogen (H ) atoms are equivalent on an orthophosphoric acid molecule, the successive K_a values differ since it is energetically less favorable to lose another H⁺ if one (or more) has already been lost and the molecule/ion is more negatively-charged. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1

Because the triprotic dissociation of orthophosphoric acid, the fact that its conjugate bases (the phosphates mentioned above) cover a wide pH range, and, because phosphoric acid/phosphate solutions are, in general, non-toxic, mixtures of these types of phosphates are often used as buffering agents or to make buffer solutions, where the desired pH depends on the proportions of the phosphates in the mixtures. Within the Brønsted - Lowry ( protonic) theory of acids and bases, a conjugate acid is the acid member HX of a pair of two compounds that transform pH is the measure of the acidity or alkalinity of a Solution. In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances For an aqueous solution composed of both a weak acid or base and its conjugate see Buffer solution. For an individual weak acid or weak base component see Buffering agent. Similarly, the non-toxic, anion salts of triprotic organic citric acid are also often used to make buffers. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. Citric acid is a weak organic Acid. It is a natural Preservative and is also used to add an acidic or sour taste to foods and Soft drinks Phosphates are found pervasively in biology, especially in the compounds derived from phosphorylated sugars, such as DNA, RNA, and adenosine triphosphate (ATP). Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy There is a separate article on phosphate as an anion or its salts. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid.

Upon heating orthophosphoric acid, condensation of the phosphoric units can be induced by driving off the water formed from condensation. When one molecule of water has been removed for each two molecules of phosphoric acid, the result is pyrophosphoric acid (H₄P₂O₇). Pyrophosphoric acid, also known under the name diphosphoric acid, is a syrupy liquid or a viscous off-white solid When an average of one molecule of water per phosphoric unit has been driven off, the resulting substance is a glassy solid having an empirical formula of HPO₃ and is called metaphosphoric acid. ^[1] Metaphosphoric acid is a singly anhydrous version of orthophosphoic acid and is sometimes used as a water- or moisture-absorbing reagent. Further dehydrating is very difficult, and can be accomplished only by means of an extremely strong desiccant (and not by heating alone). Dehydration ( hypohydration) is the removal of Water ( hydro in ancient Greek) from an object A Desiccant is a Hygroscopic substance that induces or sustains a state of dryness ( Desiccation) in its local vicinity in a moderately-well sealed container It produces phosphoric anhydride, which has an empirical formula P₂O₅, although an actual molecule has a chemical formula of P₄O₁₀. Phosphorus pentoxide is a Chemical compound with formula P 2 O 5 Phosphoric anhydride is a solid, which is very strongly moisture-absorbing and is used as a desiccant. A Desiccant is a Hygroscopic substance that induces or sustains a state of dryness ( Desiccation) in its local vicinity in a moderately-well sealed container

pH and composition of a phosphoric acid solution

For a given total acid concentration [A] = [H₃PO₄] + [H₂PO₄⁻] + [HPO₄²⁻] + [PO₄³⁻] ([A] is the total number of moles of pure H₃PO₄ which have been used to prepare 1 liter of solution) , the composition of an aqueous solution of phosphoric acid can be calculated using the equilibrium equations associated with the three reactions described above together with the [H⁺][OH⁻] = 10⁻¹⁴ relation and the electrical neutrality equation. The system may be reduced to a fifth degree equation for [H⁺] which can be solved numerically, yielding:

For large acid concentrations, the solution is mainly composed of H₃PO₄. For [A] = 10⁻², the pH is closed to pK_a1, giving an equimolar mixture of H₃PO₄ and H₂PO₄⁻. For [A] below 10⁻³, the solution is mainly composed of H₂PO₄⁻ with [HPO₄²⁻] becoming non negligible for very dilute solutions. [PO₄³⁻] is always negligible.

Phosphoric acid as a chemical reagent

Pure 75-85% aqueous solutions (the most common) are clear, colourless, odourless, non-volatile, rather viscous, syrupy liquids, but still pourable. In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances Volatility in the context of Chemistry, Physics and Thermodynamics is a measure of the tendency of a substance to Vaporize. Liquid is one of the principal States of matter. A liquid is a Fluid that has the particles loose and can freely form a distinct surface at the boundaries of Phosphoric acid is very commonly used as an aqueous solution of 85% phosphoric acid or H₃PO₄. Because it is a concentrated acid, an 85% solution can be corrosive, although nontoxic when diluted. Because of the high percentage of phosphoric acid in this reagent, at least some of the orthophosphoric acid is condensed into polyphosphoric acids in a temperature-dependent equilibrium, but, for the sake of labeling and simplicity, the 85% represents H₃PO₄ as if it were all orthophosphoric acid. In a Chemical process, chemical equilibrium is the state in which the chemical activities or Concentrations of the reactants and products have no net change Other percentages are possible too, even above 100%, where the phosphoric acids and water would be in an unspecified equilibrium, but the overall elemental mole content would be considered specified. The mole (symbol mol) is a unit of Amount of substance: it is an SI base unit, and almost the only unit to be used to measure this When aqueous solutions of phosphoric acid and/or phosphate are dilute, they are in or will reach an equilibrium after a while where practically all the phosphoric/phosphate units are in the ortho- form.

Preparation of hydrogen halides

Phosphoric acid reacts with halides to form the corresponding hydrogen halide gas (steamy fumes are observed on warming the reaction mixture). This is a common practice for the laboratory preparation of hydrogen halides.

3NaCl(s) + H₃PO₄(l) → NaH₂PO₄(s) + HCl(g)

3NaBr(s) + H₃PO₄(l) → NaH₂PO₄(s) + HBr(g)

3NaI(s) + H₃PO₄(l) → NaH₂PO₄(s) + HI(g)

Rust removal

Phosphoric acid may be used by direct application to rusted iron, steel tools, or surfaces to convert iron(III) oxide (rust) to a water-soluble phosphate compound. Iron(III oxide —also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply Rust —is Rust is a general term for a series of Iron oxides, usually red oxides formed by the reaction of Iron with Oxygen in the presence of water or air A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. It is usually available as a greenish liquid, suitable for dipping (acid bath), but is more generally used as a component in a gel, commonly called naval jelly. As a thick gel, it may be applied to sloping, vertical, or even overhead surfaces. Care must be taken to avoid acid burns of the skin and especially the eyes, but the residue is easily diluted with water. When sufficiently diluted, it can even be nutritious to plant life, containing the essential nutrients phosphorus and iron. It is sometimes sold under other names, such as "rust remover" or "rust killer. " It should not be directly introduced into surface water such as creeks or into drains, however. After treatment, the reddish-brown iron oxide will be converted to a black iron phosphate compound coating that may be scrubbed off. Iron(III phosphate, also ferric orthophosphate, or ferric phosphate, FePO4 is a Phosphate of Iron. Multiple applications of phosphoric acid may be required to remove all rust. The resultant black compound can provide further corrosion resistance (such protection is somewhat provided by the superficially similar Parkerizing and blued electrochemical conversion coating processes. Parkerizing (also called phosphating and phosphatizing) is a method of protecting a Steel surface from Corrosion and increasing its resistance Bluing is a Passivation process in which steel is partially protected against Rust, and is named after the blue-black appearance of the resulting protective finish ) After application and removal of rust using phosphoric acid compounds, the metal should be oiled (if to be used bare, as in a tool) or appropriately painted, by using a multiple coat process of primer, intermediate, and finish coats.

Processed food use

Food-grade phosphoric acid is used to acidify foods and beverages such as various colas, but not without controversy regarding its health effects. Cola is a sweet carbonated drink usually with Caramel coloring and containing Caffeine. It provides a "tangy" taste, and, being a mass-produced chemical, is available cheaply and in large quantities. The low cost and bulk availability is unlike more expensive natural seasonings that give comparable flavors, such as ginger for tangyness, or citric acid for sourness, obtainable from lemons and limes. Ginger is commonly used as a cooking spice throughout the world Citric acid is a weak organic Acid. It is a natural Preservative and is also used to add an acidic or sour taste to foods and Soft drinks The lemon ( Citrus × limon) is a hybrid in cultivated wild plants Lime is a term referring to a number of different fruits (generally Citruses, both Species and hybrids, which are typically round green to yellow (However most citric acid in the food industry is not extracted from citrus fruit, but fermented by Aspergillus niger mold from scrap molasses, waste starch hydrolysates and phosphoric acid. Aspergillus niger is a Fungus and one of the most common species of the genus Aspergillus. Molasses or Treacle is a thick Syrup by-product from the processing of the Sugarcane or Sugar beet into Sugar. Starch, CAS # 9005-25-8 Chemical formula (C6H10O5n is a Polysaccharide Hydrolysis is a Chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions which may go on to participate in further reactions ) It is labeled as E number E338. E numbers are number codes for Food additives and are usually found on Food labels throughout the European Union.

Biological effects on bone calcium and kidney health

Phosphoric acid, used in many soft drinks (primarily cola), has been linked to lower bone density in epidemiological studies. Cola is a sweet carbonated drink usually with Caramel coloring and containing Caffeine. For example, a study^[2] using dual-energy X-ray absorptiometry rather than a questionnaire about breakage, provides reasonable evidence to support the theory that drinking cola results in lower bone density. This study was published in the American Journal of Clinical Nutrition. A total of 1672 women and 1148 men were studied between 1996 and 2001. Dietary information was collected using a food frequency questionnaire that had specific questions about the number of servings of cola and other carbonated beverages and that also made a differentiation between regular, caffeine-free, and diet drinks. The paper cites significant statistical evidence to show that women who consume cola daily have lower bone density. Total phosphorus intake was not significantly higher in daily cola consumers than in nonconsumers; however, the calcium-to-phosphorus ratios were lower. The study also suggests that further research is needed to confirm the findings.

On the other hand, a study funded by Pepsi suggests that low intake of phosphorus leads to lower bone density. The study does not examine the effect of phosphoric acid, which binds with magnesium and calcium in the digestive tract to form salts that are not absorbed, but, rather, it studies general phosphorus intake. ^[3]

However, a well-controlled clinical study by Heaney and Rafferty using calcium-balance methods found no impact of carbonated soft drinks containing phosphoric acid on calcium excretion. ^[4] The study compared the impact of water, milk, and various soft drinks (two with caffeine and two without; two with phosphoric acid and two with citric acid) on the calcium balance of 20- to 40-year-old women who customarily consumed ~3 or more cups (680 ml) of a carbonated soft drink per day. They found that, relative to water, only milk and the two caffeine-containing soft drinks increased urinary calcium, and that the calcium loss associated with the caffeinated soft drink consumption was about equal to that previously found for caffeine alone. Phosphoric acid without caffeine had no impact on urine calcium, nor did it augment the urinary calcium loss related to caffeine. Because studies have shown that the effect of caffeine is compensated for by reduced calcium losses later in the day,^[5] Heaney and Rafferty concluded that the net effect of carbonated beverages – including those with caffeine and phosphoric acid - is negligible, and that the skeletal effects of carbonated soft drink consumption are likely due primarily to milk displacement.

Other chemicals such as caffeine (also a significant component of popular common cola drinks) were also suspected as possible contributors to low bone density, due to the known effect of caffeine on calciuria. Caffeine is a bitter white crystalline Xanthine Alkaloid that acts as a Psychoactive Stimulant Drug and a mild Diuretic One other study, comprised of 30 women over the course of a week, suggests that phosphoric acid in colas has no such effect, and postulates that caffeine has only a temporary effect, which is later reversed. The authors of this study conclude that the skeletal effects of carbonated beverage consumption are likely due primarily to milk displacement. ^[4] (Another possible confounding factor may be an association between high soft drink consumption and sedentary lifestyle. In statistics a confounding variable (also confounding factor, lurking variable, a confound, or confounder) is an Extraneous variable )

Cola consumption has also been linked to chronic kidney disease and kidney stones through medical research. ^[6] This study differentiated between the effects of cola (generally contains phosphoric acid), non-cola carbonated beverages (substitute citric acid) and coffee (control for caffeine), and found that drinking 2 or more colas per day more than doubled the incidence of kidney disease.

Medical use

Phosphoric acid is used in dentistry and orthodontics as an etching solution, to clean and roughen the surfaces of teeth where dental appliances or fillings will be placed. Dentistry' is the "evaluation diagnosis prevention and/or treatment (nonsurgical surgical or related procedures of diseases disorders and/or conditions of the oral cavity Orthodontics is a specialty of Dentistry that is concerned with the study and treatment of Malocclusions (improper bites which may be a result of Tooth Phosphoric acid is also an ingredient in over-the-counter anti-nausea medications that also contain high levels of sugar (glucose and fructose). Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Fructose (also levulose or laevulose) is a simple reducing Sugar ( Monosaccharide) found in many foods and is one of the three It should not be used by diabetics without consultation with a doctor. This acid is also used in teeth whiteners to eliminate any plaque that may be on your teeth.

Preparation of phosphoric acid

Phosphoric acid can be prepared by two routes - the Thermal Process and the Wet Process.

Thermal phosphoric acid: This very pure phosphoric acid is obtained by burning elemental phosphorus to produce phosphorus pentoxide and dissolving the product in dilute phosphoric acid. Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Phosphorus pentoxide is a Chemical compound with formula P 2 O 5 This produces a very pure phosphoric acid, since most impurities present in the rock have been removed when extracting phosphorus from the rock in a furnace. The end result is food-grade, thermal phosphoric acid; however, for critical applications, additional processing to remove arsenic compounds may be needed.

Wet phosphoric acid: Wet process phosphoric acid is prepared by adding sulfuric acid to calcium phosphate rock. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. Calcium phosphate is the name given to a family of Minerals containing Calcium Ions (Ca2+ together with orthophosphates (PO43-

The simplified reaction is:

3 H₂SO₄ + Ca₃(PO₄)₂ + 6 H₂O ↔ 2 H₃PO₄ + 3 CaSO₄. 2H₂O

Wet-process acid can be purified by removing fluorine to produce animal-grade phosphoric acid, or by solvent extraction and arsenic removal to produce food-grade phosphoric acid.

Other applications

Phosphoric acid is used as the electrolyte in phosphoric-acid fuel cells. An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium Phosphoric acid fuel cells ( PAFC) are a type of Fuel cell that uses liquid Phosphoric acid as an Electrolyte. It is also used as an external standard for phosphorus-31 nuclear magnetic resonance (NMR). Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15

Phosphoric acid is used as a cleaner by construction trades to remove mineral deposits, cementitious smears, and hard water stains. In the fields of Architecture and Civil engineering, construction is a process that consists of the Building or assembling of Infrastructure It is also used as an ingredient in some household cleaners aimed at similar cleaning tasks.

Hot phosphoric acid is used in microfabrication to etch silicon nitride (Si₃N₄). Microfabrication or micromanufacturing are the terms to describe processes of fabrication of miniature structures of Micrometre sizes and smaller Silicon nitride (Si3N4 is a hard solid substance It is the main component in silicon nitride Ceramics which have relatively good shock resistance It is highly selective in etching Si₃N₄ instead of SiO₂, silicon dioxide. The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide ^[7]

Phosphoric acid is used as a flux by hobbyists (such as model railroaders) as an aid to soldering. In Metallurgy, a flux is a chemical cleaning agent which facilitates Soldering, Brazing, and Welding by removing Oxidation from Soldering is a process in which two or more Metal items are joined together by melting and flowing a filler metal into the joint the filler metal having a relatively low

Phosphoric acid is also used in hydroponics pH solutions to lower the pH of nutrient solutions. Hydroponics (from the Greek words hydro (water and ponos (labour is a method of growing Plants using mineral Nutrient solutions without While other types of acids can be used, phosphorus is a nutrient used by plants, especially during flowering, making phosphoric acid particularly desirable. General Hydroponics pH Down liquid solution contains phosphoric acid in addition to citric acid and ammonium bisulfate with buffers to maintain a stable pH in the nutrient reservoir.

Phosphoric acid is used as a pH adjuster in cosmetics and skin-care products. ^[8]

Phosphoric acid is used as a chemical oxidizing agent for activated carbon production. Activated carbon, also called activated charcoal or activated coal, is a form of Carbon that has been processed to make it extremely porous and thus to ^[9]

Phosporic acid is also used for High Pressure Liquid Chromotography.

References

1. ^ phosphoric acid. The Columbia Encyclopedia, Sixth Edition. 2001-05
2. ^ Katherine L Tucker, Kyoko Morita, Ning Qiao, Marian T Hannan, L Adrienne Cupples and Douglas P Kiel (Oct 2006). "Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study". Am. J Clin. Nut. 84 (4): 936-42. PMID 17023723.  
3. ^ S. Elmståhl, B. Gullberg, L. Janzon, O. Johnell and B. Elmståhl (1998). "Increased Incidence of Fractures in Middle-aged and Elderly Men with Low Intakes of Phosphorus and Zinc". Osteoporosis International 8 (4): 333-340. doi:10.1007/s001980050072. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
4. ^ ^{a b} R. P. Heaney and K. Rafferty (2001). "Carbonated beverages and urinary calcium excretion". Am J Clin Nutr 74 (3): 343-347.  
5. ^ M. J. Barger-Lux, R. P. Heaney and M. R. Stegman (1990). "Effects of moderate caffeine intake on the calcium economy of premenopausal women [published erratum appears in Am J Clin Nutr 1991 Jan;53(1):182]". Am J Clin Nutr 52 (4): 722-725.  
6. ^ Tina M. Saldana, Olga Basso, Rebecca Darden, and Dale P. Sandler (2007). "Carbonated beverages and chronic kidney disease". Epidemiology 18 (4): 501-506. Epidemiology is the study of factors affecting the Health and Illness of populations and serves as the foundation and Logic of interventions made in the  
7. ^ Wolf, S. ; R. N. Tauber (1986). Silicon Processing for the VLSI Era: Volume 1 - Process Technology, 534. ISBN 0-961672-3-7.  
8. ^ Ingredient Dictionary: P. Cosmetic Ingredient Dictionary. Paula's Choice. Retrieved on 2007-11-16. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 534 - A second and final revision of the Codex Justinianus is published
9. ^ C. Toles, S. Rimmera and J. C. Hower (1996). "Production of activated carbons from a Washington lignite using phosphoric acid activation". Carbon 34 (11): 1419-1426. doi:10.1016/S0008-6223(96)00093-0. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  

External links

• International Chemical Safety Card 1008
• National Pollutant Inventory - Phosphoric acid fact sheet
• NIOSH Pocket Guide to Chemical Hazards
• Excel spreadsheet containing phosphoric acid titration curve, distribution diagram and buffer pH calculation
• General Hydroponics Liquid pH Down MSDS fact sheet