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The essence of Brønsted–Lowry theory is that an acid is only such in relation to a base, and vice versa. Water is amphoteric as it can act as an acid or as a base. In the image shown at the right one molecule of H 2 O acts as a base and gains H + to become H 3 O + while the other acts as an acid and loses H + to become OH − .
In chemistry, an acid–base reaction is a chemical reaction that occurs between an acid and a base.It can be used to determine pH via titration.Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid gives a proton (H +) to a base—in other words, it is a base with a hydrogen ion added to it, as it loses a hydrogen ion in the reverse reaction.
In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form hydroxide ions OH −. These ions can react with hydrogen ions (H + according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction. A base was therefore a metal hydroxide such as NaOH or Ca(OH) 2.
Arrhenius base Any substance that, when dissolved in water, increases the concentration of OH − ions, or, alternatively, decreases the concentration of hydronium ions (H 3 O +), in the resulting aqueous solution. [1] The definition is similar to that of a Brønsted–Lowry base. Contrast Arrhenius acid. arrow pushing aryl
Johannes Nicolaus Brønsted (Danish: [joˈhænˀəs ne̝koˈlɛːus ˈpʁɶnsteð]; 22 February 1879 – 17 December 1947) was a Danish physical chemist who is best known for developing the Brønsted–Lowry acid–base theory; he developed the theory at the same time as (but independently of) Martin Lowry. [1]
A Lewis base is also a Brønsted–Lowry base, but a Lewis acid does not need to be a Brønsted–Lowry acid. The classification into hard and soft acids and bases ( HSAB theory ) followed in 1963. The strength of Lewis acid-base interactions, as measured by the standard enthalpy of formation of an adduct can be predicted by the Drago–Wayland ...
What exactly this can mean depends on which definitions of acids and bases are being used. One type of amphoteric species are amphiprotic molecules, which can either donate or accept a proton (H +). This is what "amphoteric" means in Brønsted–Lowry acid–base theory.