Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 432-070-7 | CAS number: -
Dissociation constant
Administrative data
Link to relevant study record(s)
Description of key information
The pKA was determined as 7.00 ± 0.04.
Key value for chemical safety assessment
- pKa at 20°C:
- 7
Additional information
The test item reacts like a base with one proton acceptor unit, corresponding to a pKA= 7.00 of the conjugated acid. As the test item consists of several components, it was expected to find several turning points for each of the proton acceptor units which are present in the mixture. However, in all four titrations, only one point of equivalence could be detected. Therefore, it is believed, that the pKAwhich could be detected is the pKAof the reaction of the hydroxysulfinatoacetate dianion with H+ to the mono- anion overlapped by the corresponding pKAof the hydroxysulfonatoacetate dianion. The second pKA-sof both hydroxysulfinatoacetate acid and hydroxysulfonatoacetate acid are too low for a determination in aqueous systems.
The pKA-s of sodium sulphite are stated in the literature. The first pKAlies outside the determination limit in aqueous systems. The second pKAis probably overlapping with the turning point of the hydroxysulfinatoacetate respectively hydroxysulfonatoacetate dianion. It is believed that the pKA7.00 is correlated to a mixture of dissociations.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.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
