Acidul

Acidul is a Romanian noun meaning “the acid.” In Romanian grammar it is the definite form of the noun acid and is used when referring to a specific acid, for example acidul clorhidric denotes hydrochloric acid. The indefinite form is un acid. The term acid itself is used in Romanian chemistry texts to discuss acids as a class of substances.

In chemistry, acids are substances that, depending on the definition, can donate protons (Bronsted-Lowry) or accept electron pairs (Lewis). A widely used practical definition is the Arrhenius model: acids increase the concentration of hydrogen ions in aqueous solution. Acids are commonly classified as inorganic (such as hydrochloric acid HCl and sulfuric acid H2SO4) and organic (such as acetic acid CH3COOH and citric acid C6H8O7). They vary in strength from strong acids, which dissociate completely in water, to weak acids, which dissociate only partially. Their solutions typically have pH less than 7 and exhibit characteristic properties such as a sour taste, the ability to turn blue litmus red, and reactivity with active metals.

Applications of acids span many fields. They are used in chemical synthesis, metal processing, and laboratory analysis; organic acids are common in food, flavorings, and pharmaceuticals; sulfuric and phosphoric acids are essential in fertilizer production. Acids also serve pH control and buffering roles in biological and environmental contexts.

Safety and handling are important, as acids are corrosive and can cause severe burns. They require appropriate containment, compatible materials for storage, and personal protective equipment. Proper disposal and containment practices are essential to prevent environmental harm.