Wilhelm Ostwald won the 1909 Nobel Prize in Chemistry for his work on catalysis and for investigations into the fundamental principles governing chemical equilibria and rates of reaction.
Ostwald helped establish physical chemistry as a distinct scientific discipline. His research examined how chemical reactions proceed, how equilibrium is reached, and how catalysts affect reaction rates without being consumed. The Ostwald process, which produces nitric acid from ammonia, is named after him.
The award citation does not credit Ostwald with discovering catalysis itself. Instead, it recognizes his systematic scientific study of catalytic action and related chemical principles. His work helped connect laboratory measurements with mathematical descriptions of reactions.
A common mix-up is confusing Ostwald with Jacobus Henricus van 't Hoff, the first Nobel Prize winner in Chemistry, who was honored in 1901 for work on chemical dynamics and osmotic pressure. Ostwald was also an influential editor and organizer who helped promote the use of the pH scale and physical-chemistry methods.