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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.
The technique can be applied to essentially any chemical reaction in a fluid where there is an enthalpy change, although reaction kinetics can play a role in determining the sharpness of the endpoint. Thermometric titrimetry has been successfully applied to acid-base, redox, EDTA, and precipitation titrations.
The normality of a solution depends on the equivalence factor f eq for a particular reaction, which presents two possible sources of ambiguity – namely, f eq depends on the choice of reaction as well as which chemical species of the reaction is being discussed (e.g., acid/base species, redox species, precipitating salts, isotopes exchanged ...
For instance, in the case of a dibasic acid, H 2 A dissolved in water the two reactants can be specified as the conjugate base, A 2−, and the proton, H +. The following equations of mass-balance could apply equally well to a base such as 1,2-diaminoethane, in which case the base itself is designated as the reactant A:
Most familiar to those who have taken chemistry during secondary education is the acid-base titration involving a color-changing indicator, such as phenolphthalein. There are many other types of titrations, for example, potentiometric titrations or precipitation titrations.
Another possibility is that only a portion of one molecule is transferred to the other molecule. This type of reaction occurs, for example, in redox and acid-base reactions. In redox reactions, the transferred particle is an electron, whereas in acid-base reactions it is a proton. This type of reaction is also called metathesis.
Electron transfer reactions are central to myriad processes and properties in soils, and redox potential, quantified as Eh (platinum electrode potential relative to the standard hydrogen electrode) or pe (analogous to pH as -log electron activity), is a master variable, along with pH, that controls and is governed by chemical reactions and ...
At high pH, under alkaline conditions, the reaction considerably slows down because of the precipitation of Fe(OH) 3 which notably lowers the concentration of the Fe 3+ species in solution. Moreover, the pH value also directly influences the acid-base dissociation equilibrium involving the hydroperoxyl and the superoxide radicals (pK a = 4.7 ...