Registration Dossier

Diss Factsheets

Environmental fate & pathways

Hydrolysis

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

A JUSTIFICATION FOR NON-SUBMISSION OF DATA 

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.