What is a conjugate acid base pair?

A conjugate acid-base pair consists of two substances that differ only in the presence or absence of a proton. The compound that donates a proton is referred to as the acid, while the compound that accepts the proton is referred to as the base.

For example, in the reaction between hydrochloric acid (HCl) and water (H2O), HCl donates a proton to water, forming the hydronium ion (H3O+) and the chloride ion (Cl-). In this reaction, HCl acts as the acid and water acts as the base. The hydronium ion (H3O+) and the chloride ion (Cl-) form a conjugate acid-base pair.

Conjugate acid-base pairs play a crucial role in acid-base reactions, as they help maintain a balance in the concentration of protons in a solution. When an acid donates a proton, its conjugate base accepts the proton, and vice versa. This process enables the reaction to reach equilibrium and helps stabilize the pH of a solution.

In summary, a conjugate acid-base pair consists of two substances that are related by the transfer of a proton, with one compound acting as an acid and the other as a base. These pairs are essential for maintaining the pH balance in a solution and are involved in many chemical reactions.