Thank you for your kind compliments!
But please, permit a few remarks:
1). In the provided reference, it is clearly stated that …”So if solubility increases with ionic strength---meaning that concentrations increase---then activity coefficients decrease as you increase ionic strength!!”……
2). In the provided reference, it is also stated that …”Debye-Huckel equation valid from μ =0 --> 0.1 M; beyond, not very accurate at predicting activity coefficient!”
3). Moreover, it is stated therein that …” the smaller the hydrated radius--more effect of μ on activity coeff. (decrease)”…..
4). The cited schema refers to the increase of NaClO4 concentration and change of activity coefficient; but not to the increase of acid (HClO4) concentration, neither to the proton activity coefficient. Besides, ClO4- is a very bulky anion and consequently, it might not be a typical example for general conclusions.
5). By ending, HCl solubilization in water is highly exothermic and thus, fast addition of small amounts of concentrated HCl can significantly increase the HCl partial pressure and significantly decrease its Henry's constant, even at room temperature.
PS: Thinking twice, stopping posting does not sound a bad idea.