Chapter 15 Flashcards
three ways to explain acid–base behavior
Arrhenius Concept
Brønsted–Lowry Concept
Lewis Concept
Arhenius Concept of Acids and Bases
An Arrhenius acid is a substance that, when dissolved in water, increases the concentration of hydronium ion, H3O+(aq).
An Arrhenius base is a substance that, when dissolved in water, increases the concentration of hydroxide ion, OH-(aq).
Brønsted–Lowry Concept of Acids and Bases
An acid–base reaction is considered a proton (H+) transfer reaction
A Brønsted–Lowry acid
is the species donating a proton in a proton-transfer reaction; it is a proton donor.
A Brønsted–Lowry base
is the species accepting a proton in a proton-transfer reaction; it is a proton acceptor
Species that can act as both an acid and a base are called
amphiprotic or amphoteric species.
Lewis Concept of Acids and Bases
A Lewis acid is a species that can form a covalent bond by accepting an electron pair from another species.
A Lewis base is a species that can form a covalent bond by donating an electron pair to another species
The stronger an acid
the weaker its conjugate base
The weaker an acid
the stronger its conjugate base
The strength of an acid depends on
how easily the proton, H+, is lost or removed. The more polarized the bond between H and the atom to which it is bonded, the more easily the H+ is lost or donated.
For a binary acid, as the size of X in HX increases, going down a group
acid strength increases.
For a binary acid, going across a period, as the electronegativity increases
acid strength increases.
For a series of oxoacids differing only in the central atom Y
the acid strength increases with the electronegativity of Y.
The acid strength of a polyprotic acid and its anions decreases with
increasing negative charge.
A reaction will always go in the direction from
stronger acid to weaker acid, and from stronger base to weaker base
