Brønstedhappokatalyyttejä

Brønsted-Lowry acid-base theory, often referred to as the Brønsted concept, defines an acid as a proton donor and a base as a proton acceptor. This definition expands upon the earlier Arrhenius theory, which was limited to aqueous solutions and specified acids as substances that produce hydrogen ions and bases as substances that produce hydroxide ions. The Brønsted-Lowry theory is more general and applicable to reactions in non-aqueous solvents and even in the gas phase.

In a Brønsted-Lowry acid-base reaction, a proton (H+) is transferred from the acid to the base. For example, when hydrogen chloride (HCl) dissolves in water, HCl acts as a Brønsted acid by donating a proton to water, which acts as a Brønsted base. This results in the formation of hydronium ions (H3O+) and chloride ions (Cl-). The conjugate base of an acid is the species that remains after the acid has donated a proton. Similarly, the conjugate acid of a base is the species formed after the base has accepted a proton. For instance, in the reaction of HCl with water, Cl- is the conjugate base of HCl, and H3O+ is the conjugate acid of water. Understanding conjugate acid-base pairs is crucial for predicting the direction of acid-base reactions. The strength of an acid is inversely related to the strength of its conjugate base, and vice versa.