How to describe the enthalpy of acid dissociation in aqueous solutions?

How to describe the enthalpy of acid dissociation in aqueous solutions?
If we had a weak acid "PB" that dissociates to give a proton and a conjugate base. Classically it would be described like the following:


[![enter image description here](https://i.stack.imgur.com/Abt2G.png)](https://i.stack.imgur.com/Abt2G.png)


Unfortunately, things aren't that simple in aqueous solutions. Each of the dissociated molecules will have a charge which will change its polarity and water hydration (solvation).


a better way would be to describe dissociation in gas phase then the solvation of each:
[![enter image description here](https://i.stack.imgur.com/D5QMM.png)](https://i.stack.imgur.com/D5QMM.png)


[![enter image description here](https://i.stack.imgur.com/Hfypm.png)](https://i.stack.imgur.com/Hfypm.png)


Is this description accurate? Is the enthalpy of protonation measured by calorimetry or calculated by the Van't Hoff analysis the "dissociation" or the "Ionization"? 


