A Swedish physicist and chemist who did fundamental work on physical chemistry. He worked with van’t Hoff in Amsterdam and proposed a theory of activated molecules and established a connection between rate of reaction and absolute temperature. He also developed a theory for electrolytic dissociation based on van’t Hoff’s results and stated that any acid, base, or salt dissolved in water is partly split up into positively and negatively charged ions, and that they move in opposite directions on electrolysis. He was awarded a Nobel Prize for Chemistry in 1903.

http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1903/arrhenius-lecture.html Official website of the Nobel Prize organization, with a transcript of Arrhenius’ lecture of 1903.