Description: The term ‘acid’ refers to a class of chemical compounds characterized by having a pH less than 7 and the ability to donate protons (H+) in a solution. Acids are fundamental in chemistry and biology, as they participate in numerous chemical reactions and metabolic processes. Their corrosive nature and ability to react with bases to form salts are distinctive properties. Acids can be classified into strong acids, which completely dissociate in solution, and weak acids, which only partially dissociate. Additionally, acids can be organic, such as acetic acid found in vinegar, or inorganic, such as hydrochloric acid. The identification of an acid can be performed using pH indicators, which change color in the presence of an acid. In everyday life, acids are ubiquitous, from the foods we consume to the cleaning products we use. Their study is essential for understanding the chemistry of living beings and industrial processes.
History: The concept of acid dates back to antiquity, where philosophers like Aristotle discussed the nature of substances. However, it was in the 18th century that acids began to be classified more systematically. Antoine Lavoisier, in 1777, proposed the theory of acids based on the presence of oxygen, although this idea was later refuted. By the late 19th century, Svante Arrhenius defined acids as substances that release protons in aqueous solution, laying the groundwork for the modern theory of acids and bases.
Uses: Acids have a wide variety of applications in different fields. In the chemical industry, they are used for the production of fertilizers, plastics, and pharmaceuticals. In food, organic acids like citric acid are used as preservatives and flavorings. In laboratories, acids are essential for conducting chemical reactions and analyses. Additionally, acids are used in cleaning and disinfection, as they can remove stains and bacteria.
Examples: Examples of acids include hydrochloric acid (HCl), which is used in industry and laboratories; sulfuric acid (H2SO4), a key component in battery manufacturing; and acetic acid (CH3COOH), found in vinegar. Another example is citric acid, present in fruits like lemons and used in the food industry.
