Hydronium ion

The hydronium ion (H₃O⁺) is a water molecule (H₂O) that has gained an extra proton (H⁺). When acids dissolve in water, they release these protons, which quickly attach to water molecules, forming hydronium ions. This ion is responsible for the sour taste of acids and the conduction of electricity in acidic solutions. Essentially, the hydronium ion is water with an additional positive charge, playing a key role in the chemistry of acids and bases.