What is a Bronsted-Lowry acid defined as?

A Bronsted-Lowry acid is defined as a proton donor. This definition is fundamental to the Bronsted-Lowry theory of acids and bases, which emphasizes the transfer of protons (H⁺ ions) during chemical reactions. When a substance donates a proton to another substance, it acts as a Bronsted-Lowry acid. For instance, in the reaction between hydrochloric acid (HCl) and water, HCl donates a proton to water, making HCl a Bronsted-Lowry acid.

Understanding this concept is critical in the study of acid-base chemistry, as it lays the groundwork for how acids and bases interact in various chemical environments. The significance of the proton transfer is that it highlights the dynamic nature of acid-base chemistry beyond mere definitions based on proton concentration or presence of hydroxide ions.