The formula for the hydronium ion is _____.

HO 3
H 3O +
H +
OH -

The correct formula for the hydronium ion is H3O+.

To arrive at this answer, it's helpful to understand that the hydronium ion is formed when a water molecule (H2O) gains a hydrogen ion (H+) through the process of protonation. This protonation occurs when an acid, a substance that donates a proton (H+), reacts with water. The proton combines with a water molecule to form the hydronium ion.

It's worth noting that the hydronium ion and the hydroxide ion (OH-) are both important components in the context of acids and bases. The hydronium ion represents the acidic nature, while the hydroxide ion represents the basic nature.

H3O+

https://en.wikipedia.org/wiki/Hydronium