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Dissociation constant

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Reference
Endpoint:
dissociation constant
Type of information:
other: handbook data
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Adopted according to OECD SIDS or other official EU regulatory procedures (public available peer-reviewed source)
Principles of method if other than guideline:
Handbook data, no further details
GLP compliance:
no
Dissociating properties:
yes
No.:
#1
pKa:
>= 9.9 - <= 12
Temp.:
30 °C

Consideration of the high dissociation constants of silicic acid (pKa 9.9, 11.8, 12 & 12 at 30 °C) leads to the conclusion that at environmental pH values of 6.5 – 8.5 only a small proportion of silicate ions will be in solution.

Description of key information

pKa 9.9, 11.8, 12 at 30 °C

Key value for chemical safety assessment

Additional information

Consideration of the high dissociation constants of silicic acid leads to the conclusion that at environmental pH values of 6.5 ¿ 8.5 only a small proportion of silicate ions will be in solution (Lide & Frederikse 1995).