alkali
Enable an agent to recognise an alkali, assess its composition and condition, and judge its suitability for a specified 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 agent to recognise an alkali, assess its composition and condition, and judge its suitability for a specified use.
An alkali is a water-soluble base that produces an aqueous solution with increased hydroxide-ion activity and can neutralize acids.
It can be Classify a candidate material against an explicit alkali definition.; Compare identified alkali preparations using compatible assay and concentration bases.; Assess whether a stored preparation needs resampling or reassay before use.; Estimate neutralisation demand from a specified analytical endpoint and validated capacity.; Evaluate dilution, transfer and material-contact proposals against preparation-specific evidence.; Select or reject an alkali grade against an intended use's purity and performance requirements..
Distinguishing features
Require both evidence of basic behaviour in water and solubility information under stated conditions; the label 'base' alone is insufficient.
Distinguish a substance or preparation identified as an alkali from a sample described only as alkaline by its measured pH.
Use chemical composition to distinguish alkalis from alkali metals; membership of the elemental family does not establish this material identity.
Separate hydroxide concentration, measured pH and titratable neutralising capacity; none alone establishes the identity or amount of every alkaline constituent.
Treat classification as potentially terminology-dependent for carbonates, aqueous ammonia and sparingly soluble hydroxides, and record the convention used.
Scope
+ The operational meaning of alkali and evidence that a material qualifies
+ Chemical constituents, grade, purity and relevant impurities
+ Dissolution, aqueous speciation, pH and neutralising capacity under stated conditions
+ Physical form and changes caused by storage or exposure
+ Preparation-specific hazards, compatibility and fitness for an intended use
- Alkali metals as an elemental family
- Bases that do not meet the selected aqueous-solubility criterion
- Alkalinity as a property of arbitrary waters or mixtures
- Finished cleaners, foods or other products containing an alkali
- Industrial manufacturing processes and treatment equipment
Characteristics
- Alkali classification convention
- Named definition or operational criterion, with inclusion and exclusion decisions Prevents different uses of the word alkali from silently changing the model boundary.
- Constituent identity
- Chemical species and applicable CAS, PubChem CID or EC identifiers, each with provenance A class label cannot supply the chemical identity needed for compatibility or hazard assessment.
- Composition and grade
- Constituent and impurity mass fractions in %, with analytical basis and grade specification Water, carbonate and other impurities can change effective strength and suitability.
- Physical form
- Solid, aqueous solution, slurry or other documented form; temperature in °C Form affects sampling, transfer and interpretation of concentration.
- Water solubility
- g solute per 100 g water at a stated temperature, with species and method Supports the class boundary and identifies limits on preparing a homogeneous solution.
- Alkali concentration
- mol/L, mol/kg or mass %, with named constituent, temperature where relevant and conversion basis Supports preparation and dosing without confusing different concentration conventions.
- Aqueous pH
- Dimensionless pH, with temperature, dilution, method and uncertainty Describes the measured aqueous condition but does not replace composition or neutralising-capacity data.
- Titratable neutralising capacity
- mol H+ neutralised per kg or L of sample, with titration endpoint and method Expresses acid demand under a defined test rather than inferring it from pH.
- Exposure and alteration condition
- Documented moisture exposure, carbon dioxide exposure, contamination, precipitation and assay history Changes during storage can invalidate nominal composition or concentration.
- Applicable hazard classification
- Classification and evidence for the identified composition, concentration, physical form and jurisdiction The generic word alkali is insufficient to assign handling requirements.
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.alkali
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 19 findings · 29 questions.
Alkali identity and boundary Establish what the word alkali means for the material being recorded.
Alkali is a class term whose boundary must be resolved before identifiers or properties can be assigned.
Classification convention
Record the definition and evidence used to include a candidate.
Aqueous base membership
Establish membership through documented basic behaviour and water solubility.
- Which definition of alkali governs this record, and what solubility criterion does it require? definition
- What evidence establishes basic behaviour and dissolution in water under the recorded conditions? measurement
Chemical referent
Resolve the class name to the actual substance or preparation.
Species versus trade label
Separate chemical constituents from commercial or historical uses of the word alkali.
- Which chemical species or mixture does this material label denote, and which source establishes that identity? provenance
- Do any supplied CAS, EC or PubChem identifiers describe the actual constituent, hydrate or mixture rather than a neighbouring chemical identity? boundary
Composition and effective strength Describe what the alkali contains and how much reactive material is available.
Nominal purity, dissolved concentration and acid-neutralising capacity answer different operational questions.
Grade and assay
Record constituent amounts and the basis of purity claims.
Active content and impurities
Resolve alkali content separately from water and other constituents.
- Is the assay reported as received, on a dry basis, as a named compound or as an equivalent amount of another compound? measurement
- Which limits apply to water, carbonate and use-relevant impurities, and what lot-specific evidence supports compliance? provenance
Neutralisation capacity
Record a method-defined measure of acid demand.
Endpoint-dependent capacity
Tie reported strength to titration conditions and included constituents.
- What acid, endpoint and analytical method define the reported neutralising capacity? measurement
- Does the result distinguish hydroxide from carbonate or other basic constituents, or report their combined acid demand? boundary
Aqueous behaviour and phase Connect dissolution, aqueous chemistry and physical state to measurement conditions.
An alkali's useful behaviour cannot be inferred from its name without concentration, temperature and phase information.
Dissolution and phase limits
Establish whether the recorded material is dissolved, saturated or multiphase.
Dissolved versus total content
Separate dissolved alkali from material present in undissolved phases.
- At the recorded temperature and composition, is the preparation homogeneous, saturated or carrying undissolved solids? measurement
- Does the concentration describe the liquid phase or the entire preparation, and how was the sample taken? boundary
pH and speciation
Interpret aqueous basicity using measurement conditions and constituent chemistry.
Interpretable pH
Keep measured pH distinct from concentration and inferred chemical species.
- At what temperature and dilution was pH measured, and was the method suitable for this sample? measurement
- Which basic species are supported by composition or analysis, and what assumptions would be needed to infer hydroxide activity from them? definition
Storage and chemical change Track exposure-driven changes that may alter alkali identity, concentration or usability.
A preparation's current strength and condition may differ from its original certificate or label.
Air and moisture exposure
Assess the relevance of atmospheric water and carbon dioxide to the identified alkali.
Exposure-related drift
Establish whether documented exposure has changed the preparation.
- For this composition and container history, what evidence supports changes from water exchange or carbon dioxide uptake? provenance
- Which measurements would distinguish changed water content from conversion of basic constituents? measurement
Current condition and requalification
Determine whether stored material remains represented by its recorded assay.
Assay validity after storage
Connect observed changes to reassessment before use.
- Have caking, crystallisation, phase separation or contamination been observed, and how do they affect representative sampling? measurement
- What storage event, elapsed interval or analytical deviation requires reassay or rejection for the intended use? action
Safe and fit use Relate the actual preparation to handling constraints and application requirements.
Alkali identity alone cannot establish safe contact materials, preparation methods or acceptable substitution.
Handling and compatibility
Resolve hazards and contact constraints for the stated concentration and form.
Preparation-specific constraints
Anchor handling decisions in evidence for the actual alkali preparation.
- Which current safety data and applicable classifications cover this exact composition, concentration and physical form? provenance
- What documented constraints govern dilution, neutralisation and contact with proposed containers, metals, seals or other reagents? action
Application and substitution
Determine which alkali properties control acceptance for a specified task.
Use-specific equivalence
Assess suitability beyond matching nominal pH or alkali mass.
- Does the intended use require a particular pH, neutralising capacity, constituent identity, impurity limit or combination of these? action
- If another alkali is proposed, which differences in counterions, reaction products, solubility and required dose prevent or permit substitution? boundary
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.
- The intended sense is a chemical class, not an individual substance, commercial formulation or historical ash-derived material.
- Terminology varies over inclusion of ammonia and sparingly soluble hydroxides; check the registry's intended boundary.
- Melting point, boiling point, purity specifications, exposure limits and regulatory classifications require a specific compound, hydration state and formulation.
- Which of these check these first hold for the sense of alkali this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Alkali-metal hydroxides, such as sodium hydroxide and potassium hydroxide
- Soluble basic carbonates, such as sodium carbonate and potassium carbonate
- Sparingly soluble alkaline-earth hydroxides, conventionally including calcium hydroxide
- Which of these kinds and varieties hold for the sense of alkali 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 - 1310-73-2 - Sodium hydroxide; alkali as a class has no single CAS number.
- CAS Registry Number - 1310-58-3 - Potassium hydroxide.
- CAS Registry Number - 497-19-8 - Anhydrous sodium carbonate; hydrated forms have separate identities.
- Which of these identifiers and schemes hold for the sense of alkali 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 Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS): hazard classification depends on the particular substance or mixture and its concentration.
- Which of these standards and regulation hold for the sense of alkali this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Neutralizing acidic process streams and adjusting water-treatment pH
- Manufacturing soap through alkaline hydrolysis of fats
- Removing grease and other soils in cleaning formulations
- Providing alkaline conditions for pulp and paper processing
- Supplying sodium compounds for glass manufacture, particularly through sodium carbonate
- Which of these real-world use hold for the sense of alkali this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Aqueous solution pH - Above 7 at 25 °C; the value depends on composition, concentration and activity effects - dimensionless
- Alkalinity or acid-neutralizing capacity - No class-wide range; determined by titration to a specified endpoint - mmol of hydrogen-ion equivalents/L
- Which of these typical measurements hold for the sense of alkali 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 caustic alkalis can cause severe skin burns and eye damage.
- Dissolving solid hydroxides or diluting concentrated solutions can release substantial heat and cause splashing.
- Reaction with acids can generate heat; carbonate alkalis also release carbon dioxide.
- Some strong alkalis attack aluminium or zinc and can release flammable hydrogen.
- Absorption of atmospheric carbon dioxide can change composition and reduce the effective strength of hydroxide reagents.
- Which of these failure modes and hazards hold for the sense of alkali this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Commercial names such as lye, caustic soda and soda vary in usage; chemical identity and concentration should be stated explicitly.
- Which of these regional variation hold for the sense of alkali 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.
- base - Base is the broader category; an alkali must dissolve sufficiently in water to produce an alkaline solution.
- alkali metal - An alkali metal is a Group 1 metallic element; an alkali is a basic substance, commonly a compound.
- alkaline solution - An alkaline solution is a mixture with basic aqueous conditions; alkali identifies the base responsible for those conditions.
- alkalinity - Alkalinity is a measured acid-neutralizing capacity, not a substance or simply another name for pH.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of alkali this model covers, and on what evidence? provenance
What the second pass must settle
- Which authoritative definition should govern this registry entry, particularly for carbonates, aqueous ammonia and sparingly soluble hydroxides?
- Does an existing Vercy world model already own this alkali concept or the shared base behaviour to which this entry should link?
- Should commercial mixed alkalis be instances of this model or linked preparations governed primarily by a mixture model?
- Which analytical methods and endpoints should make alkali strength comparable across hydroxide, carbonate and mixed preparations?
- Which intended uses and jurisdictions should determine the required grade specifications, hazard records and exposure-limit references?