Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.

Diss Factsheets

Environmental fate & pathways


Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information


Key value for chemical safety assessment

Additional information

The active substance, hydrochloric acid, is used as an aqueous solution (33-36%). Hydrochloric acid is a strong acid that is very soluble in water and dissociates completely (Cl- is a very weak conjugate base, therefore the reaction goes to completion), to form chloride ion and hydronium ions. 

               HCl + H2O --> H3O+ + Cl-

As a result of the complete dissociation of HCl in water, the concentration of the resultant hydronium ions is equal to the concentration of the HCl introduced to the solution and for the purpose of calculating the resultant pH the reaction may be written as: 

               HCl (aq) --> H+ + Cl-

pH is calculated as -log10[H+], where the units of hydrogen ion concentration are moles/litre (molarity). 

As hydrochloric acid dissociates in water, effects are due to hydronium and chloride ion concentrations and the major result of dissolution of HCl in water is the resulting pH.

Thus, due to these intrinsic properties, it is scientifically impossible to perform the hydrolysis test. In addition, since the behaviour of HCl in water is known, it is also not scientifically necessary to perform a hydrolysis test.