levelling effect

https://doi.org/10.1351/goldbook.L03506
The tendency of a solvent to make all @B00744@ whose @A00079@ exceeds a certain value appear equally acidic. It is due to the complete transfer to a @P04916@ solvent of a @H02904@ from a dissolved acid stronger than the @C01266@ of the solvent. The only acid present to any significant extent in all such solutions is the @L03654@. For example, the solvent water has a levelling effect on the acidities of HClO4 , HCl and HI : aqueous solutions of these acids at the same (moderately low) concentrations have the same acidities. A corresponding levelling effect applies to strong bases @P04904@ solvents.
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1135 [Terms] [Paper]