phosphoric acid
Enable an AI agent to recognise phosphoric acid, assess a particular material's composition and condition, and determine whether its documented grade and handling controls support an intended use.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an AI agent to recognise phosphoric acid, assess a particular material's composition and condition, and determine whether its documented grade and handling controls support an intended use.
Phosphoric acid, understood here as orthophosphoric acid, is the inorganic phosphorus(V) oxoacid H3PO4, a triprotic acid whose successive deprotonation produces dihydrogen phosphate, hydrogen phosphate and phosphate ions.
It can be Resolve a supplier label or batch record to orthophosphoric acid and flag ambiguous phosphate identities.; Compare a batch's concentration and impurity evidence with a named application specification.; Assess whether observed crystallisation or changes in flow are consistent with recorded composition and temperature.; Calculate acid quantities or dilution requirements from an explicit concentration basis, subject to an approved handling procedure.; Select applicable safety documentation and assess container or transfer-system compatibility.; Hold a batch for further testing when identity, contamination or grade evidence is insufficient..
Distinguishing features
Identity evidence specifies orthophosphoric acid, H3PO4, rather than using 'phosphoric acids' as an unspecified family name.
Composition distinguishes an acid-water material from a phosphate salt containing counterions; phosphate detected in solution alone does not establish phosphoric acid identity.
Where condensed acids may be present, analytical evidence distinguishes orthophosphate species from species containing phosphorus-oxygen-phosphorus linkages.
An aqueous solution states its H3PO4 concentration and basis; it is not treated as pure acid merely because its product name says 'phosphoric acid'.
Materials with the same acid identity are distinguished by documented grade and impurity limits rather than assumed interchangeable.
Scope
+ Orthophosphoric acid identity, molecular composition and verified registry identifiers
+ Pure material and aqueous solutions with explicit concentration and reporting basis
+ Grade, impurity profile and batch-specific evidence of suitability
+ Phase, acid-base behaviour and physical properties under stated conditions
+ Concentration-specific hazards, storage compatibility and jurisdiction-specific controls
- Phosphate salts and their independent material specifications
- Polyphosphoric and metaphosphoric acids as independently specified substances
- Fertilisers, beverages, cleaners and other formulated products containing phosphoric acid
- Industrial manufacturing plants and complete production-process models
- Biological phosphate metabolism and clinical treatment models
Characteristics
- Substance identity
- Orthophosphoric acid; formula H3PO4; verified CAS, PubChem and EC identifiers Prevents confusion with phosphate salts, condensed acids and broad commercial names.
- Acid concentration
- Mass fraction as % H3PO4; other bases retained explicitly with any conversion assumptions Controls interpretation of properties, dosing, hazards and grade specifications.
- Water content
- % by mass, with analytical method and uncertainty Distinguishes pure material from aqueous solutions and supports composition checks.
- Phosphate speciation
- Orthophosphate and condensed-phosphate fractions, with basis and method Tests whether the material remains within the orthophosphoric-acid boundary.
- Material grade
- Supplier-declared technical, food, reagent, electronic or other grade, tied to a named specification Grade names alone cannot establish suitability for a particular application.
- Impurity profile
- Analyte-specific mg/kg or other stated units, including detection limits Trace metals, fluoride and other relevant contaminants can constrain use independently of acid concentration.
- Physical state and temperature
- Liquid, crystalline solid or mixed phase; temperature in °C A material's phase must be judged against its concentration and thermal history.
- Condition-dependent physical properties
- Density in kg/m³, viscosity in mPa·s, transition temperatures in °C and pressure in kPa, each linked to composition Supports transfer and storage decisions without applying pure-substance values to solutions.
- Acidity measurement
- pH with measurement conditions; titratable acidity with endpoint and reporting basis Separates measured acidity from nominal H3PO4 concentration and phosphate speciation.
- Applicable safety and regulatory evidence
- Links to current SDS, jurisdiction, concentration range, exposure limits and use-specific requirements Makes handling and eligibility decisions traceable to the actual material and applicable rules.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.phosphoric-acid
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 17 findings · 25 questions.
Orthophosphoric acid identity Establishes which chemical entity the registry entry covers and how a supplied material relates to it.
Phosphoric acid, phosphate salts and condensed phosphoric acids must not be conflated through naming or a phosphate assay.
Chemical identity
Connects the orthophosphoric-acid interpretation to authoritative identity records.
Identity record
Record H3PO4 identity and verified identifier mappings, retaining the source and any naming ambiguity.
- Does the registry's phosphoric-acid entry specifically denote orthophosphoric acid? definition
- Which authoritative records verify its CAS number, PubChem CID, EC number and accepted synonyms? provenance
Phosphate boundaries
Distinguishes acid-water material from salts, condensed acids and formulated mixtures.
Species and mixture boundary
Assess counterions, condensed phosphate species and intentionally added ingredients when classifying a sample.
- What evidence distinguishes this material from a phosphate salt solution or a mixture containing condensed phosphoric acids? boundary
- Do additional ingredients require a separate formulated-product model linked to this substance? boundary
Concentration, grade and purity Describes the acid-water composition and the evidence supporting a batch's claimed quality.
Phosphoric acid concentration and impurity limits determine whether nominally identical materials can serve the same purpose.
Composition and assay
Makes assay results interpretable across concentration conventions and analytical methods.
Acid content basis
Record whether results express H3PO4, phosphorus, P2O5 equivalent or titratable acidity, without treating those measures as interchangeable.
- What is the measured acid content, its reporting basis, analytical method and uncertainty? measurement
- Does the assay distinguish orthophosphoric acid from other phosphorus species or other contributors to acidity? measurement
Grade and contaminants
Connects a declared grade to batch evidence and application-specific impurity limits.
Batch suitability evidence
Assess the certificate of analysis against a named specification, including relevant contaminants and analytical detection limits.
- Which specification defines the claimed grade, and which batch certificate demonstrates compliance? provenance
- Which limits for metals, fluoride, other anions or organic contamination must this batch meet for its intended use? action
Physical state and acid behaviour Relates observable material condition and chemical behaviour to composition and operating conditions.
A single melting point, boiling point or acidity value cannot characterise every phosphoric acid solution.
Phase and flow
Assesses crystallisation, density, viscosity and thermal behaviour for the actual concentration.
Condition-specific properties
Attach composition, temperature and pressure to physical-property evidence and distinguish phase change from composition-changing thermal events.
- At the measured acid concentration and temperature, what phase, density and viscosity are expected? measurement
- Does a reported thermal transition describe melting, water loss, boiling or dehydration, and under what pressure and composition? boundary
Acidity and reaction state
Tracks acidity and the extent to which dilution or neutralisation changes the material's interpretation.
Acidity and neutralisation
Record pH and titration conditions separately from total phosphorus and nominal acid concentration.
- What measurement conditions and titration endpoint support the reported pH or acid-equivalent content? measurement
- Has neutralisation introduced sufficient counterions to require describing the material as a phosphoric-acid/phosphate mixture? boundary
Handling and use eligibility Connects the material's concentration and grade to documented handling controls and permitted applications.
The phosphoric-acid name alone does not establish hazard classification, equipment compatibility or eligibility for food and other controlled uses.
Exposure and containment
Assesses the supplied material's hazards, possible mist exposure and storage or transfer compatibility.
Material-specific controls
Use concentration-specific safety evidence and compatibility data covering the actual temperature, impurities and contact materials.
- Which current SDS and jurisdiction-specific exposure limits apply to this concentration and to acid mist generated by the proposed operation? provenance
- What evidence supports the selected container, seals, transfer equipment and dilution procedure under the intended conditions? action
Application release
Determines whether a batch may enter an intended use and when uncertainty requires a hold.
Use-specific acceptance
Tie acceptance to the relevant specification, jurisdiction and batch evidence rather than the supplier's grade label alone.
- Which composition, purity and regulatory requirements govern the intended food, laboratory, industrial or electronic application? action
- Which missing records, failed limits or signs of contamination require testing, rejection or restricted use? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This is recall-based information; no sources were consulted.
- Verify current compendial editions, jurisdiction-specific classifications and exposure limits before regulatory use.
- Physical properties depend strongly on concentration and temperature; heating can cause dehydration to condensed acids, so a boiling-point value requires careful qualification.
- Which of these check these first hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Anhydrous orthophosphoric acid
- Aqueous phosphoric acid solutions
- Technical-grade phosphoric acid
- Food-grade phosphoric acid
- Pharmaceutical-grade phosphoric acid
- Reagent-grade phosphoric acid
- Which of these kinds and varieties hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- CAS Registry Number - 7664-38-2 - Identifies phosphoric acid; does not specify concentration or grade.
- PubChem CID - 1004 - Compound record for phosphoric acid.
- EC number - 231-633-2 - European substance identifier.
- Food additive INS / E number - INS 338 / E338 - Food additive identity; does not establish permission for every food category or jurisdiction.
- Which of these identifiers and schemes hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- United States Pharmacopeia: Food Chemicals Codex specifications for phosphoric acid used as a food ingredient.
- United States Pharmacopeia-National Formulary: compendial requirements for pharmaceutical phosphoric acid.
- FAO/WHO Joint Expert Committee on Food Additives: identity and purity specifications for phosphoric acid.
- United Nations: Globally Harmonized System of Classification and Labelling of Chemicals; locally implemented classifications depend on the supplied material.
- Which of these standards and regulation hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Manufacture of phosphate fertilizers and phosphate salts.
- Food and beverage acidulation using material meeting applicable food-grade requirements.
- Metal cleaning, rust removal and phosphate conversion treatment.
- Dental enamel and dentine etching in formulated products.
- Laboratory pH adjustment and preparation of phosphate buffer systems.
- Which of these real-world use hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Molar mass - 97.99 - g/mol
- Melting point of pure anhydrous acid - Approximately 42.3 - °C
- Common concentrated commercial solution strength - 75-85 - % by mass H3PO4
- Density of an 85% by mass aqueous solution near 20 °C - Approximately 1.69 - g/cm³
- Successive aqueous acid dissociation constants near 25 °C - pKa1 ≈ 2.15; pKa2 ≈ 7.20; pKa3 ≈ 12.35 - dimensionless
- Which of these typical measurements hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Concentrated material is corrosive and can cause severe skin burns and eye damage.
- Acid mist can injure or irritate the respiratory tract despite the acid's low volatility.
- Dilution and neutralization release heat and can cause splashing or localized overheating.
- Contact with susceptible metals can release flammable hydrogen gas.
- Unsuitable grades can introduce impurities into food, pharmaceutical or analytical applications.
- Which of these failure modes and hazards hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Food additive identification commonly uses E338 in Europe and INS 338 in international additive nomenclature; permitted uses vary by jurisdiction.
- Occupational exposure limits and legally required hazard labels depend on jurisdiction and, for supplied solutions, concentration.
- Which of these regional variation hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Phosphorous acid - H3PO3 contains phosphorus in oxidation state +3 and is diprotic, whereas phosphoric acid contains phosphorus in oxidation state +5 and is triprotic.
- Polyphosphoric acid - Contains condensed phosphorus acids with P-O-P bonds; orthophosphoric acid has no P-O-P linkage.
- Phosphate salts - Contain phosphate-derived anions with counterions and are distinguished from the parent acid by their composition and degree of neutralization.
- Phosphoric acid formulations - Products such as dental etchants or rust removers contain phosphoric acid together with water and other ingredients; their properties are formulation-specific.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of phosphoric acid this model covers, and on what evidence? provenance
What the second pass must settle
- Does the registry intend orthophosphoric acid alone, and does an existing world model already cover that identity?
- Which authoritative sources establish the identifier mappings and concentration-dependent physical properties, including the interpretation of reported boiling or decomposition temperatures?
- Which analytical criteria adequately distinguish orthophosphoric acid from condensed-acid mixtures in commercial materials?
- Which named grade standards and impurity limits should anchor the initial application profiles?
- Which jurisdictions and supplied concentrations must be covered first for GHS classification, exposure limits, transport requirements and use eligibility?