Question

What are the strongest acid and strongest base that can exist in water?

Answer 1

The strongest acid is `H_3O^+`; the strongest base is `HO^-`. These definitions refer to AQUEOUS solution.

Explanation:

Any acid/base system is modified by the particular properties of the solvent. In water, the hydronium ion, `H_3O^+`, is conceived to be the strongest acid in solution, and hydroxide ion, `HO^-` is conceived to be the strongest base. Additions of acids and bases modify the respective equilibrium concentrations.

On the other hand, there is the opportunity of using other solvent systems. Sulfuric acid allows a more acidic regime: here the acid base system is conceived to be `HSO_4^(-)"/"H_3SO_4^+`; liquid ammonia allows excursion into the basic regime (`NH_2^(-)"/"NH_4^+`). For both examples, the chemist would have to take fairly severe and rigorous precautions to eliminate water. Non-aqueous chemistry is fairly demanding.