Content
Acid is considered to be any compound that dissociates in aqueous solution liberates hydrogen ions (H+) and reacts with water molecules to generate hydronium ions (H3OR+). Acids are formed by the combination of an oxide and water, and as a consequence the resulting solution acquires an acid pH, that is, lower than 7.
Bases, on the other hand, are formed by compounds that in an aqueous solution release hydroxyl ions (OH '') and cause the pH of the solution to exceed pH 7.
History
This way of defining acids and bases is the oldest and is part of the Arrhenius theory, which dates from the late nineteenth century. Some years later, Brönsted and Lowry defined acids as those substances that can give up a proton (H+) and bases like those that can accept a proton (H+) given by an acid. Already entered the twentieth century, Lewis determined that an acid is a substance capable of sharing or accepting a pair of electrons, while a base can share or give a pair of electrons.
characteristics
Acids are generally sour and corrosive; bases are also corrosive, with a caustic taste and soapy touch. The tendency of an acid to dissociate and lower the pH is often referred to as "acid strength." Are examples of strong acids perchloric, sulfuric, hydroiodic, hydrobromic, hydrochloric and nitric.
Similarly, they can be considered as strong bases potassium, sodium, lithium and magnesium hydroxide. Acetic, citric, and benzoic acids, on the other hand, are weak acids; ammonia is a weak base.
How are salts formed?
The you go out are ionic compounds of varying complexity, are abundant in nature and are formed by the combination of acids with bases, generating a release of water. The salts can be neutral, acidic or basic. In the former, all the hydrogen atoms in the acid have been replaced by a metal cation. Acid salts, on the other hand, retain one or more hydrogen atoms.
In turn, salts can be double or triple if they contain more than one cation or more than one anion. For example, calcium potassium fluoride is a double neutral salt (CaKF3), because it contains two different cations. Finally, it is worth mentioning the basic salts, in which at least one anion is the hydroxide anion, for example, in the trihydroxide of copper chloride (Cu2Cl (OH)3).
On the other hand, they are known as ternary salts or tertiary to those obtained by combining a metal with a radical, such as sulfate, carbonate or dichromate, and as quaternary ammonium salts those in which all the hydrogen atoms of the ammonium have been replaced by radicals, as in the case of tetramethylammonium chloride.
Distribution and importance
The acids They are extremely important both in industry and in nature. For example, hydrochloric acid is part of our digestive system and is necessary for us to break down the nutritional compounds present in food. Deoxyribonucleic acid, better known as DNA, makes up the chromosomes, which is where the genetic information necessary for living things to multiply and develop is encoded. Boric acid is a prominent component in the glass industry.
The calcium carbonate It is a very abundant salt in various types of limestone rocks. By the action of high temperatures (900 ° C), calcium carbonate is obtained into calcium oxide or quicklime. Adding water to quicklime produces calcium hydroxide, called slaked lime, which is a base. These materials are used in construction.
