Explain: Proton $(H^{+})$ does not exist in aqueous solution.

(N/A) hydrogen ion $(H^{+})$ by itself is a bare proton with a very small size $(\sim 10^{-15} \ m$ radius) and an intense electric field.
Therefore,the proton binds itself to a water molecule at one of the two available lone pairs via a coordinate covalent bond,forming the hydronium ion $(H_{3}O^{+})$.
This hydronium ion $(H_{3}O^{+})$ has a trigonal pyramidal geometry. The existence of the $H_{3}O^{+}$ species has been confirmed in various compounds,such as $H_{3}O^{+}Cl^{-}$ in the solid state.
Similarly,the hydronium ion can be further hydrated to form several other ionic species,such as $H_{5}O_{2}^{+}$,$H_{7}O_{3}^{+}$,and $H_{9}O_{4}^{+}$.
Thus,a proton does not exist independently in an aqueous solution; instead,it exists as a hydronium ion or other hydrated oxonium ions.