Question

Why does hydrogen ion combines with a water molecule to form a hydronium ion?

• A. To form complex ions
• B. It cannot exist on its own
• C. It is stable
• D. None of the above

Answer 1

The correct option is B It cannot exist on its own

A hydrogen ion cannot exist on its own, so it combines with a water molecule to form a hydronium ion. It is the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a proton (a positive hydrogen ion, $H^{+}$) to the surrounding water molecules $\left(H_{2}O\right)$.