hydrogen ion

In a solution, an acid is a chemical that will release hydrogen ions — atoms with a tiny positive charge.

While most hydrogen bonds in water are weak, strong hydrogen bonds similar to the ones found in the bifluoride ions can form in water that contains excess hydrogen ions.

That is, different concentrations of hydrogen-ion or of hydroxide-ion are required to change their colors.

It is very likely that in aqueous acids, a large proportion, at least, of the hydrogen-ion is similarly combined with water.

The hydrogen-ion will very decidedly reduce the concentration of the acetate-ion, acetic acid being a weak acid (table, p. 104).

As a weak acid, acetic acid produces much less hydrogen-ion than is formed in equivalent solutions of sulphuric acid.

We call each a “hydrogen ion” but you can see that each is a single proton.