الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
The early classification of a group of substances into acids and bases was based on empirical observations of chemical properties rather than on theoretical concepts. In the seventeenth century, acids and bases were defined as substances which combine to form salts. Toward the end of the eighteenth century, Lavoisier (1777) proposed a de-finition based on composition; he considered oxygen as the constituent which imparts acid properties to an acid. How¬ever, this definition was disproved by Davy (1810), who showed that hydrochloric acid is composed of hydrogen and chlorine only. In 1838, Leibig stated that acids are com¬pounds which contain hydrogen and in which the hydrogen can be replaced by a metal. This definition, based on ”composi¬tion” and ”reactivity”, became generally accepted.