Search results
Results From The WOW.Com Content Network
[5] [6] [7] In the Brønsted–Lowry theory acids and bases are defined by the way they react with each other, generalising them. This is best illustrated by an equilibrium equation. acid + base ⇌ conjugate base + conjugate acid. With an acid, HA, the equation can be written symbolically as:
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.
In the more general Brønsted–Lowry acid–base theory (1923), a base is a substance that can accept hydrogen cations (H +)—otherwise known as protons. This does include aqueous hydroxides since OH − does react with H + to form water, so that Arrhenius bases are a subset of
In the above example, acetate is the base of the reverse reaction and hydronium ion is the acid. One hallmark of the Brønsted–Lowry theory in contrast to Arrhenius theory is that it does not require an acid to dissociate. The essence of Brønsted–Lowry theory is that an acid only exists as such in relation to a base, and vice versa.
Johannes Nicolaus Brønsted and Martin Lowry introduced the Brønsted–Lowry theory, which said that any compound that can give a proton to another compound is an acid, and the compound that receives the proton is a base. A proton is a subatomic particle in the nucleus with a unit positive electrical charge.
As an acid, losing a proton: HCO − 3 + OH − ⇌ CO 2− 3 + H 2 O As a base, accepting a proton: HCO − 3 + H + ⇌ H 2 CO 3 Note: in dilute aqueous solution the formation of the hydronium ion , H 3 O + (aq) , is effectively complete, so that hydration of the proton can be ignored in relation to the equilibria.
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 ...
The strength of an acid varies from solvent to solvent. An acid which is strong in water may be weak in a less basic solvent, and an acid which is weak in water may be strong in a more basic solvent. According to Brønsted–Lowry acid–base theory, the solvent S can accept a proton. + + +