Final answer:
Using the Brønsted-Lowry theory, acids are substances that donate protons (H+), while bases accept protons. This classification is key to understanding acid-base reactions in chemistry.
Step-by-step explanation:
Under the Brønsted-Lowry theory in chemistry, an acid is defined as a substance that can donate a proton (H+), and a base is a substance that can accept a proton. For example, when acetic acid (HCOOH) dissolves in water, it donates a proton to water, forming hydronium ions (H3O+) and acetate ions (HCOO−), acting as a Brønsted-Lowry acid. Conversely, when water acts as a proton acceptor, as seen in the reaction with phosphate ion (PO43−), where water accepts a proton and transforms into hydroxide ions (OH−), it functions as a Brønsted-Lowry base.
The classification of a compound as an acid or base is essential in understanding acid-base reactions because they are prevalent in many chemical reactions, including those in biological systems.