Registration Dossier
Registration Dossier
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EC number: 211-656-4 | CAS number: 681-84-5
Dissociation constant
Administrative data
Link to relevant study record(s)
Description of key information
Dissociation constant (tetramethyl orthosilicate): not relevant
Dissociation constant (silicic acid): pKa1 = 9.9
Key value for chemical safety assessment
Additional information
The requirement to test the substance for dissociation constant is waived because in contact with water the substance hydrolyses very rapidly. The hydrolysis products in this case are silicic acid and methanol. Silicic acid was reported to have dissociation constant values of pKa1 = 9.9, pKa2 = 11.8, pKa3 and pKa4 = 12 at 30°C in a secondary data source which has been subject to peer review and in which the original sources are traceable.
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