What is the relationship between the strongest base and its conjugate acid?

The correct relationship is that a strong base is paired with the weakest acid. This stems from the principles of acid-base theory, particularly the concept of conjugate acid-base pairs. In the Brønsted-Lowry definition, an acid is a proton donor, and a base is a proton acceptor. When a base accepts a proton, it forms its conjugate acid.

If we consider a strong base, it has a great tendency to attract protons, meaning it is very effective at pushing the equilibrium of acid-base reactions towards the formation of its conjugate acid. As a result, the conjugate acid of a strong base must be weak, because a strong base must correspond to a weak acid in acid-base chemistry. This relationship ensures that the strong base can effectively accept protons and that the resulting conjugate acid does not readily donate protons in solution, which is characteristic of weak acids.

Thus, since the strongest base is paired with the weakest acid, this confirms why this relationship is essential in understanding acid-base behavior in chemical reactions.