Guillaume François Rouelle (, 15 September 1703 – 3 August 1770) was a French

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

and

apothecary ''Apothecary'' () is a mostly archaic term for a medical professional who formulates and dispenses '' materia medica'' (medicine) to physicians, surgeons, and patients. The modern chemist (British English) or pharmacist (British and North Ameri ...

. In 1754 he introduced the concept of a base into chemistry as a substance which reacts with an

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

to form a

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

). He is known as ''l'Aîné'' (the elder) to distinguish him from his younger brother,

Hilaire Rouelle Hilaire Marin Rouelle (15 February 1718 – 7 April 1779) was an 18th-century French chemist. Commonly cited as the 1773 discoverer of urea, he was not the first to do so. Dutch scientist Herman Boerhaave had discovered this chemical A chem ...

, who was also a chemist and known as the discoverer of

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important r ...

. He started a public course in his laboratory in 1738 where he taught many students among whom were

Denis Diderot Denis Diderot (; ; 5 October 171331 July 1784) was a French philosopher, art critic, and writer, best known for serving as co-founder, chief editor, and contributor to the ''Encyclopédie'' along with Jean le Rond d'Alembert. He was a promine ...

, Antoine-Laurent de Lavoisier,

Joseph Proust Joseph Louis Proust (26 September 1754 – 5 July 1826) was a French chemist. He was best known for his discovery of the law of definite proportions in 1794, stating that chemical compounds always combine in constant proportions. Life Joseph L. ...

and

Antoine-Augustin Parmentier Antoine-Augustin Parmentier (, , ; 12 August 1737 – 13 December 1813) was a French pharmacist and agronomist, best remembered as a vocal promoter of the potato as a food source for humans in France and throughout Europe. His many other contribu ...

. He was elected a foreign member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences ( sv, Kungliga Vetenskapsakademien) is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special ...

in 1749.

Why bases for neutral salts were called bases

The modern meaning of the word "base" and its general introduction into the chemical vocabulary are usually attributed to the French chemist, Guillaume-François Rouelle (1703–1770), who used the term "Base" in a memoir on salts written in 1754 (see The Origin of the Term "Base" by

William B. Jensen William B. Jensen (born March 25, 1948 in Marshfield, Wisconsin) is an American chemist and chemical historian. Jensen, son of a sign painter and librarian, went to school in Wausau, Wisconsin. He became interested in chemistry at an early age and ...

). In this paper, which was an extension of an earlier memoir on the same subject written in 1744, Rouelle pointed out that the number of known salts had increased significantly during the 17th and early 18th centuries. This was due not only to the preparation of new salts, but also to an increasing ability to distinguish between sodium and potassium compounds, and to a generalization of the concept so as to include many substances, such as the

alums An alum () is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula , where is a monovalent cation such as potassium or ammonium. By itself, "alum" often refers to potassium alum, with the f ...

and vitriols (i.e.,

sulfates The sulfate or sulphate ion is a polyatomic A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge t ...

), that had been previously excluded. In order to incorporate this extended concept of salt formation, Rouelle explicitly defined a neutral salt as the product formed by the union of an acid with any substance, be it a water-soluble alkali, a volatile alkali, an absorbent earth, a metal, or an oil, capable of serving as "a base" for the salt "by giving it a concrete or solid form".Source https://www.physicsforums.com/threads/etymology-of-base.543937/

Why bases for neutral salts were called bases

References

Further reading