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Diss Factsheets
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EC number: 206-059-0 | CAS number: 298-14-6
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Dissociation constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- dissociation constant
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: expert judgement
- Principles of method if other than guideline:
- The dissociation constants for CO2 in water are reported.
- GLP compliance:
- not specified
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 6.35
- Temp.:
- 25 °C
- Remarks on result:
- other: fresh water
- No.:
- #2
- pKa:
- 10.33
- Temp.:
- 25 °C
- Remarks on result:
- other: fresh water
- No.:
- #1
- pKa:
- 5.86
- Temp.:
- 25 °C
- Remarks on result:
- other: seawater
- No.:
- #2
- pKa:
- 8.95
- Temp.:
- 25 °C
- Remarks on result:
- other: seawater
- Conclusions:
- The dissociation constants of CO2 in water systems are reported to be 6.35 (pK1) and 10.33 (pK2) at 25°C in fresh water and 5.86 (pK1) and 8.95 (pK2) at 25°C in seawater.
- Executive summary:
In the review article, the dissociation constants of CO2 in water systems are reported to be 6.35 (pK1) and 10.33 (pK2) at 25°C in fresh water and 5.86 (pK1) and 8.95 (pK2) at 25°C in seawater ( H2CO3 <=> HCO3- <=> CO32 -).
- Endpoint:
- dissociation constant
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study with acceptable restrictions
- Principles of method if other than guideline:
- Apparent molar volumes VΦ and apparent molar heat capacities Cp, Φ of aqueous potassium carbonate and potassium bicarbonate solutions were determined. Corrections for speciation due to hydrolysis and disproportionation in solution were applied using Young's rule, and semi-empirical equations were fitted to the experimental results. Based on the results several thermodynamic properties were determined. The pK2 for potassium hydrogencarbonate determined at several temperatures.
- GLP compliance:
- not specified
- Dissociating properties:
- yes
- No.:
- #2
- pKa:
- 10.34
- Temp.:
- 25 °C
- Conclusions:
- The pK2 of potassium hydrogencarbonate is reported to be 10.335 at 25 °C.
- Executive summary:
The pK2 of potassium hydrogencarbonate is reported to be 10.335 at 25 °C.
Referenceopen allclose all
In the review article, the dissociation constants of CO2 in water systems are reported to be 6.35 (pK1) and 10.33 (pK2) at 25°C in fresh water and 5.86 (pK1) and 8.95 (pK2) at 25°C in seawater ( H2CO3 <=> HCO3- <=> CO32 -).
The pK2 of potassium hydrogencarbonate is reported to be 10.335 at 25 oC.
Description of key information
Potassium hydrogencarbonate dissociates in water completely to K+ and inorganic carbon (CO32- ions in equilibrium with HCO3- and CO2). The dissociation constants of CO2 in water systems are 6.35 (pK1) and 10.33 (pK2) at 25°C in fresh water and 5.86 (pK1) and 8.95 (pK2) at 25°C in seawater (CO2 (solv) + H2O <=> H2CO3 => HCO3- => CO32-).
Key value for chemical safety assessment
- pKa at 20°C:
- 6.35
Additional information
The pK of potassium hydrogencarbonate at 25 °C is 6.35 (pK1) and 10.33 (pK2).
The dissociation constants of CO2 in water systems are 6.35 (pK1) and 10.33 (pK2) at 25°C in fresh water and 5.86 (pK1) and 8.95 (pK2) at 25°C in seawater (H2CO3=> HCO3-=> CO32-).
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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