What is a hydrated proton?

Answer 1

When an acid, such as hydrochloric acid or HCl, is added to water, the hydrogen and chlorine split apart forming two ions: H+ and Cl-. The H+ is what makes the acid acidic -- in other words it is the active ingredient in an acid. And because a hydrogen atom only has one proton and one electron in its neutral state, when you have H+, it consists of nothing more than a proton.

A lone proton is extremely unstable and this is due to the very high density of charge. It has a single positive charge, but that charge is located on an extremely tiny object (the proton). When in water, the H+ ions will combine with water molecules immediately to form H3O+. You will never find free protons in a water solution -- all are combined with water to form H3O+. Now, that single positive charge is distributed over a much much larger volume because it can be spread out over several atoms in the molecule instead of one single proton (and remember, even a single atom is much much bigger than a proton). H3O+ is called hydronium, and is also referred to as a hydrated proton -- because it is really a water molecule with one extra proton.

Answer 2

it is known as hydronium ion (H3O+) with respect to oxygen it is also oxonium ion.