What does a conjugate base represent?

A conjugate base is defined as the species that remains after an acid donates a proton (H⁺) to a base. When an acid loses a proton during a chemical reaction, what is left over is the conjugate base of that acid. This relationship between acids and bases is a fundamental concept in acid-base theory, specifically in the Brønsted-Lowry definition, which emphasizes the role of proton transfer.

For example, if we consider acetic acid (CH₃COOH) as the acid, when it donates a proton, it converts into its conjugate base, acetate (CH₃COO⁻). Therefore, the key feature that defines a conjugate base is its formation from an acid after the loss of a proton. This understanding is crucial for predicting how acids and bases will interact in chemical reactions and for calculating pH levels in various solutions.