The hydronium ion H3O+ is the strongest acid that can exist in aqueous solution because stronger acids dissociate by transferring a proton to water. What is the strongest base that can exist in aqueous solution?

Acid-base theory explains the behavior of acids and bases in chemical reactions. According to the Brønsted-Lowry theory, acids are proton donors, while bases are proton acceptors. In aqueous solutions, the strength of an acid is determined by its ability to donate protons to water, forming hydronium ions (H3O+). This framework is essential for understanding the interactions between acids and bases in solution.

Dissociation refers to the process by which an acid breaks apart in solution to release protons. Strong acids, like HCl, completely dissociate in water, producing a high concentration of H3O+ ions. This complete dissociation is what makes them strong acids. Understanding this concept is crucial for identifying the strongest acid and, by extension, the strongest base that can exist in aqueous solution.

Conjugate acid-base pairs are related species that differ by the presence of a proton. When an acid donates a proton, it forms its conjugate base, while the base that accepts the proton becomes its conjugate acid. In the context of the question, the strongest base in aqueous solution is the conjugate base of the strongest acid, which is the hydroxide ion (OH-) since it can accept a proton to form water.