Transcript Acid-Base Properties of Salt Solutions

Acid-Base Properties of Salt
Solutions
 Salts are solids at room
temperature composed of
cations and anions arranged
in a crystal lattice (i.e. ionic
compounds).
 When salts dissolve in water,
they dissociate into aqueous
solutions of ions that may or
may not affect the pH of a
solution.
Salts that Form Neutral
Solutions
 Salts with the cation of a strong
base and the anion of a strong
acid. (eg NaCl, K2SO4)
Salts that Form Acidic
Solutions
 Salts where the cation is the
conjugate acid of a weak base
and the anion of a strong acid.
(eg NH4Cl)
 Non-metal oxides (eg CO2)
 Salts where the cation is a highly
charged metal ion and the anion
is from a strong acid. (eg AlCl3)
Salts that Form Basic Solutions
 Salts with the cation of strong
base and the anion of a weak
acid. (eg NaC2H3O2)
 Metal oxides (eg CuO)
Special Cases
 The pH of a salt where the
cation is the conjugate acid of
a weak base and the anion is
the conjugate base of the
weak acid will depend on the
Ka value of the conjugate acid
and the Kb value of the
conjugate base.
If Ka> Kb, pH will be acidic
Ka< Kb, pH will be basic
Ka= Kb, pH will be neutral
Summary and Homework
 Steps for predicting the Acid-Base
Behaviour of a salt page 585
 Summary Chart page 592
 Page 588 #1-5