Registration Dossier

Diss Factsheets

Physical & Chemical properties

Dissociation constant

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

For pH between 4 and 6, all chlorine is present as hypochlorous acid HClO.
For pH inferior to 4, the main species is chlorine Cl2.
For pH higher than 5, the dissociation of the hypochlorous acid increases up to pH 9 where this dissociation is total. At pH 9, all chlorine is present as hypochlorite ion ClO-.

Key value for chemical safety assessment

Additional information

No study is available. Handbook data indicate that sodium hypochlorite can undergo several reactions in water. The main reaction is the dissociation of the hypochlorous acid with K=2.9x10 -8 (at 25°C), pKa=7.53 (Pinto, 2003) The various species present in solution are: For pH between 4 and 6, all chlorine is present as hypochlorous acid HClO. For pH inferior to 4, the main species is chlorine Cl2. For pH higher than 5, the dissociation of the hypochlorous acid increases up to pH 9 where this dissociation is total. At pH 9, all chlorine is present as hypochlorite ion ClO-.

Categories Display