Svante August Arrhenius was a Swedish physical chemist best known for his theory that electrolytes, certain substances that dissolve in water to yield a solution that conducts electricity, are separated, or dissociated, into electrically charged particles, or ions, even when there is no current flowing through the solution. In 1903 he was awarded the Nobel Prize for Chemistry.
Svante August Arrhenius was born in Wijk, Sweden on February 19, 1859, the son of Svante Gustaf Arrhenius and Carolina Christina Thunberg. His ancestors were farmers; his uncle became Professor of Botany and Rector of the Agricultural High School at Ultuna near Uppsala and later Secretary of The Swedish Academy of Agriculture. His father was a land surveyor employed by the University of Uppsala and in charge of its estates at Wijk, where Svante was born.
Arrhenius is said to have taught himself to read at the age of three and to have become interested in mathematics from watching his father add columns of figures. The family moved to Uppsala in 1860. The boy was educated at the Cathedral school where the rector was a good physics teacher. From an early age Svante had shown an aptitude for arithmetical calculations, and at school he was greatly interested in mathematics and physics. Svante August Arrhenius graduated from high school as the youngest and brightest in his class.
Arrhenius as a student
In 1876 he entered the University of Uppsala, studying mathematics, chemistry and physics. The practical instruction in physics was not of the best, and in 1881 he went to Stockholm to work under Professor E. Edlund at the Academy of Sciences. Here, Arrhenius began by assisting Edlund in his work on electromotive force measurements in spark discharges but soon moved to an interest of his own.
This resulted in his thesis (1884) “Recherches sur la conductibilite galvanique des electrolytes” (Investigations on the galvanic conductivity of electrolytes). From his results the author concluded that electrolytes, when dissolved in water, become to varying degrees split or dissociated into electrically opposite positive and negative ions.
The degree to which this dissociation occurred depended above all on the nature of the substance and its concentration in the solution – being more developed the greater the dilution. The ions were supposed to be the carriers of the electric current, e.g. in electrolysis, but also of the chemical activity. The relation between the actual number of ions and their number at great dilution (when all the molecules were dissociated) gave a quantity of special interest (“activity constant”).
Arrhenius as a student
The idea of a connection between electricity and chemical affinity, once advocated by Berzelius, had, however, so completely vanished from the general consciousness of scientists that the value of Arrhenius’ publication was not well understood by the science faculty at Uppsala, where the dissertation took place. Arrhenius’s thesis was received coolly by the university authorities and nearly ruined his prospects for an academic career.
At the time his theory seemed incredible to many because, among other reasons, a solution of sodium chloride shows none of the characteristics of either sodium or chlorine, and, in addition, the professors he had shunned in his studies were not well disposed toward him.
The faculty at Uppsala were skeptical of hypotheses and devoted to accurate experimental work, while Arrhenius boasted (not quite truly) that he had never performed an exact experiment in his life; moreover, his subject fell awkwardly between chemistry and physics.
Even to the sympathetic English physicist Sir Oliver Lodge, who in 1886 described the theory to the British Association for the Advancement of Science, Arrhenius seemed sometimes “to indulge in . . . manipulation of imaginary data,” producing “a confusion” from which emerged so-called theoretical deductions. In reality, Arrhenius had a statistical sense and an ability to frame formulas to fit his facts, both of which were rare among chemists of his day.
Hindsight shows that this young chemist had both great data and a revolutionary explanation, but neither the logic nor the data could change the mind set of the established chemists. Yet in the end his persistence and his model prevailed. He has been recognized by the professional societies and the Nobel Prize committee. This is the story that needs to be told to high school students. At the age of 24, Arrhenius had determined the conductivity of many electrolytes and planned his dissertation proposal. His data may have taken the following format:
The resistance of an electrolyte is increased when the dilution is doubled.
In very dilute solutions the conductivity is nearly proportional to the concentration.
The conductivity of a solution is equal to the sum of conductivities of the salt and the solvent.
If these laws are not observed, it must be due to a chemical reaction between the substances including the solvent.
The electrical resistance rises with increasing viscosity, complexity of the ion, and the molecular mass of the solvent. (incorrect)
Arrhenius concluded from the above statements that the “molecule” breaks apart into a positive fragment and negative fragment, called ions, by its interaction with the solvent.
This was a great leap in thinking. The concept of dissociation did not come at first but developed as time allowed Arrhenius to talk with other chemists. By 1887 Arrhenius had worked out the language of his model with statements like “In all probability all electrolytes are completely dissociated at extreme dilutions”.
He could explain weak and strong acids by the concentration of the ions, known as percent dissociation today. Data continued to support the concept that ionic and polar covalently bonded substances dissociate in water. Some substances dissociate to a greater extent. These statements explain the colligitave properties and differences in pH of similar acid concentrations.
Arrhenius had the foresight to send copies of his thesis to several international chemists, and a few were impressed with his work, including the young chemists Wilhelm Ostwald and Jacobus Henricus van’t Hoff, who were also to become founding fathers of physical chemistry. Otto Pettersson, Professor of Chemistry at Stockholms HOgskola, emphasized the originality of the dissertation, and Wilhelm Ostwald travelled to Uppsala to make the acquaintance of the young author.
The fundamental importance of Arrhenius’ work was thus made clear. Ostwald offered Arrhenius a position in Riga, Latvia, which Arrhenius could not then accept because of his father’s illness. He was instead given a post in Sweden and later a travel grant from the Swedish Academy that enabled him to work with Ostwald and van’t Hoff. He subsequently developed his electrolytic dissociation theory further in quantitative terms and wrote texts promoting physical chemistry.
Arrhenius & Ostwald
Through Edlund’s influence he was awarded a travelling fellowship from the Academy of Sciences which enabled him to work in 1886 with Ostwald in Riga and with Kohlrausch in Wurzburg. In 1887 he was with Boltzmann in Graz and in 1888 he worked with van’t Hoff in Amsterdam.
During these years Arrhenius was able to prove the influence of the electrolytic dissociation on the osmotic pressure, the lowering of the freezing point and increase of the boiling point of solutions containing electrolytes. Later on he studied its importance in connection with biological problems such as the relationship between toxins and antitoxins, serum therapy, its role for digestion and absorption as well as for the gastric and pancreatic juices. The paramount importance of the electrolytic dissociation theory is today universally acknowledged, even if certain modifications have been found necessary.
In 1891, Arrhenius declined a professorship offered to him from Giessen, Germany, and soon afterwards he obtained a lectureship in physics at Stockholms HOgskola. In 1895 he became Professor of Physics there. He was in addition Rector from 1897 to 1905, when he retired from the professorship.
He had got an invitation to a professorship in Berlin, and the Academy of Sciences then decided (1905) to start a Nobel Institute for Physical Chemistry with Arrhenius as its chief. Initially he had to work in a rented flat, but a new building was inaugurated in 1909. A large number of collaborators came to him from Sweden and from other countries, and helped to give his ideas wider currency.
In 1900 Arrhenius published his Larobok i teoretisk elektrokemi (Textbook of theoretical electrochemistry), in 1906 followed Theorien der Chemie (Theories of Chemistry) and Immunochemistry and in 1918 the Silliman lectures Theories of solutions.
He took a lively interest in various branches of physics, as illustrated by his theory of the importance of the CO2-content of the atmosphere for the climate, his discussion of the possibility that radiation pressure might enable the spreading of living spores through the universe (panspermy) and by his various contributions to our knowledge of the northern lights. In 1903 appeared his Lehrbuch der kosmischen Physik (Textbook of cosmic physics).
Although he was offered opportunities to move to other European universities, and he delivered important lecture series at universities in the United States, Arrhenius always returned to Stockholm. In the late 1890′s when electrically charged subatomic particles were discovered, Arrhenius’ ionic theory suddenly made sense. In 1903 he received the Nobel Prize in chemistry in recognition of the extraordinary services he has rendered to the advancement of chemistry by his electrolytic theory of dissociation.
Many lectures and short publications gave witness of his interest and capacity for writing for the general public. Especially during the last decades of his life he published a number of popular books, which were usually translated into several languages and appeared in numerous editions. To these belong Varldarnas utveckling (1906, Worlds in the Making), Stjarnornas Oden (1915, Destiny of the Stars) and others. In 1913 appeared Smittkopporna och deras bekampande (Smallpox and its combating) and in 1919 Kemien och det moderna livet (Chemistry and modern Life).
Arrhenius was elected a Foreign member of the Royal Society in 1911, and was awarded the Society’s Davy medal and also the Faraday Medal of the Chemical Society (1914). Among the many tokens of distinction that he received were honorary degrees from the Universities of Birmingham, Cambridge, Edinburgh, Greifswald, Groningen, Heidelberg, Leipzig and Oxford.
In an extension of his ionic theory Arrhenius proposed definitions for acids and bases. He believed that acids were substances which produce hydrogen ions in solution and that bases were substances which produce hydroxide ions in solution. It is interesting that neither Bronsted nor Lewis received the Nobel Prize for continuing the work on the theory of acids and bases and for expanding the definition of these substances. It is noted that Arrhenius never did accept the Bronsted or Lewis definitions of acids and bases.
Arrhenius studied reaction rates as a function of temperature, and in 1889 he introduced the concept of activation energy as the critical energy that chemicals need to react. Arrhenius also applied physicochemical principles to the study of meteorology, cosmology, and biochemistry. In meteorology he anticipated late twentieth-century speculation on the “greenhouse” effect of carbon dioxide in the atmosphere when small changes in the concentration of carbon dioxide in the atmosphere could considerably alter the average temperature of a planet.
Arrhenius was a genial, energetic man who made many friends on his visits abroad. His memory was excellent, he loved nature, but he was indifferent to the fine arts and literature.
His range of scientific interests was very wide: over the years, he moved away from the study of solutions into immunology, where he made pioneering studies on toxins, and then into geology and cosmology. In Worlds in the Making (1908), he suggested that cool stars might collide and form nebulae from which new stars and planets would arise; and so the process would go on indefinitely, life being spread about the universe by bacteria propelled by light pressure. These speculations have not found their way into modern cosmology.
Svante Arrhenius with a group biologists
Svante Arrhenius with unknown people, in 1896, is seated on the table to the right of center
Arrhenius was a contented man, happy in his work and in his family life. During the First World War, he made successful efforts to release and repatriate German and Austrian scientists who had been made prisoners of war. He was twice married – in 1894 to Sofia Rudbeck, by whom he had one son, and in 1905 to Maria Johansson by whom he had one son and two daughters. He died at Stockholm on October 2, 1927, and is buried at Uppsala.
Pictures at left show Svante Arrhenius with very different groups of people.
Bust of S. Arrhenius at the Arrhenius Institute in Stockholm.
The Arrhenius medal of the Swedish Academy of Sciences, 1937, to memorize the discovery of the water dissociation.
You may benefit by reading the Arrhenius paper introducing the electrolyte theory:
“On the Dissociation of Substances Dissolved in Water”
Zeitschrift fur physikalische Chemie, 1887, I, 631 (translation in English)
“On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground”
Philosophical Magazine, 1896, 41, 237-276.