Question

Give a reason for the following. 

Hydronium ions are always in the form H₃O⁺.

Answer 1

When acids dissolve in water. The H⁺ ion from acid always goes to the nearest water molecule to form a hydronium ion.

HCl(aq) + H₂O(aq) → H₃O⁺(aq) + Cl^-(aq)

For example: When Hydrochloric acid(HCl) is a strong acid. When it is dissolved in water, HCl is ionized completely in an aqueous solution. Hydrochloric acid will donate its proton H⁺ to a water molecule to form a hydronium cation H₃O⁺ and chloride anions Cl^-.