acid dissociation constant



acid dissociation constant or acidity constant symbol: Ka; the thermodynamic equilibrium constant for the dissociation of an acid. For a dilute solution of a weak acid, HA, dissociating in water according to the equilibrium:

HA + H2O  ↔ H3O+ + A,
Ka = (aH3O+ × aA–)/aHA

where a is the activity of the species designated by the subscripts. The activity of the water has been omitted from the equation since it may be taken as unity for a dilute aqueous solution. Ka is a measure of the strength of the acid, i.e. of its ability to donate hydrons to water.



مقالات قد تفيدك :

أضف تعليق

كلمات دليلية: ,