The term "Arrhenius" primarily refers to Svante Arrhenius, a Swedish scientist known for his contributions to physical chemistry. He is best known for the Arrhenius equation, which describes how the rate of a chemical reaction depends on temperature and activation energy. This equation is fundamental in understanding reaction kinetics and is widely used in various scientific fields. Arrhenius also proposed the concept of acid-base theory, which classifies acids as substances that produce hydrogen ions (H⁺) in solution and bases as those that produce hydroxide ions (OH⁻). His work laid the groundwork for modern chemistry, influencing both theoretical and practical applications in the study of chemical reactions.