The ability of an acid to lose its ion determines the strength of the acid.
In a solution, a strong acid gets completely ionised (dissociates).
We can also say that the less the value of the pH is, the more the strength of the acid.
For example, the strongest acid known is (Fluoroacetic acid), as its electron-withdrawing inductive effect is the strongest among the other halogens present.
Therefore, the example of the strongest acid is fluoro acetic acid .