Are there actual #H^+# or #H_3O^+# ions in aqueous solution?
It would not be my rationalization.......
Water is a so-called protic solvent, and it can exchange protons with itself, and with other species in solution. We represent this reaction by the so-called autoprotolysis reaction:
Under standard conditions of temperature and pressure, we measure the extent of this equilibrium:
So back to your question (finally!), we CONCEIVE of the acidium species in water as
Are you happy with this treatment?