Davy, Humphry, hydrochloric acid

Carl Wilhelm Scheele (1742-1786) discovered chlorine in the reaction of hydrochloric acid with manganese dioxide (pyrolusite or brownstone ore). Recognized as an element by Sir Humphry Davy (1778-1829). 

In 1787 William Cruikshank (1745-1795) isolated, but did not identify, strontium from the mineral strontianite he examined. In 1790 Dr. Adair Crawford (1748—1794), an Irish chemist, discovered strontium by accident as he was examining barium chloride. He found a substance other than what he expected and considered it a new mineral. He named the new element strontium and its mineral strontianite after a village in Scotland. In 1808 Sir Humphry Davy treated the ore with hydrochloric acid, which produced strontium chloride. He then mixed mercury oxide with the strontium chloride to form an amalgam alloy of the two metals that collected at the cathode of his electrolysis apparatus. He heated the resulting substance to vaporize the mercury, leaving the strontium metal as a deposit. 

In later years, Gay-Lussac continued to advance science. He developed a precise method for analyzing the alcoholic content of liquors and patented a method for the manufacture of sulfuric acid. His last publication on aqua regia (a mixture of nitric and hydrochloric acids that dissolves gold or platinum) came out the year before his death in 1850. Gay-Lussac was a top-notch experimentalist and theoretician. More than twenty-five years after Gay-Lussac died, the prominent chemist Marcellin Bertholet (1827-1907) once said, We all teach. . . the chemistry of Lavoisier and Gay-Lussac (Crosland, p. 248), a fitting tribute to two outstanding scientists of the era. see also Acid-Base Chemistry Berthollet, Claude-Louis Charles, Jacques Dalton, John Davy, Humphry Lavoisier, Antoine. 

Synthesis and Reactivity Chlorine was first prepared by the Swedish chemist K.W. Scheele in 1774 using the reaction of manganese dioxide with hydrochloric acid. Erroneously, he thought that it was a compound of oxygen, and ultimately it was named and identified as an element by Sir Humphry Davy in 1810. The reaction of hydrochloric acid with potassium permanganate provides a second convenient route to small quantities of chlorine. 

Amalgams with the alkali metals are readily formed by plunging the latter into warmed mercury. They are of interest in that by using a mercury cathode, Sir Humphry Davy in 1807 was able to isolate both potassium and sodium by electrolysis of potash and soda (p. 144). Mercury is used to-day in the commercial manufacture of caustic soda and hydrochloric acid by the electrolysis of brine. It is used also as the raw material for the preparation of mercuric oxide, vermilion, mercurous and mercuric chloride, fulminate and other derivatives. The oxide is of special historical interest as it led 170 years ago to the discovery of oxygen (p. 21)... 

The non-metal oxide reactions with water led Antoine Laurent Lavoisier (1713-1794) to associate the acidity principle with elemental oxygen, but Sir Humphry Davy, in the beginning of the XIX century, was the first to suggest that the acidifying principle was owed to hydrogen — as in the case of hydrochloric acid. 

Discovery Chlorine was discovered by Carl Wilhelm Scheele in 1774. He obtained it in the reaction between the mineral pyrolusite and hydrochloric acid (HCI, then known as muriatic acid). Scheele thought the resulting gas contained oxygen. Sir Humphry Davy proved that chlorine was an element and gave it its present name. 

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