18.3 ACID-BASE PROPERTIES OF SALT SOLUTIONS(SALT HYDROLYSIS) (Summary)
Dissolving Animation: http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/molvie1.swf
Salts:
 strong ________________ (i.e. conduct an ______________ current when ____________
or______________)
 composed of ___________ and ____________ in a rigid _______________ lattice
*Hydrolysis (“water splitting”)  a reaction of an ion with water to produce an ____________ or
____________ solution (i.e. hydronium or hydroxide ions)
*How to determine whether or not a given salt will initiate a hydrolysis reaction(after being
dissolved)…and alter the pH of a solution:
GUIDELINE #1: A salt (i.e. ionic compound) containing the conjugate base of a ___________ acid
will produce a ______________ solution when dissolved in water.
Example:
Salt = sodium ethanoate, NaC2H3O2(s)
*This salt contains the conjugate of what weak acid?__________________
2 (l )
Dissociation equation: NaC2H3O2(s) 

H O
Hydrolysis equation:
**METAL CATIONS FROM GROUPS ___ and ___ on the periodic table, for our purposes, DO
NOT react with water (i.e. do not alter the pH). Conversely, ___________, ____________
charged(usually 3+) metal ions (usually _______________ metals and aluminum) DO REACT with
water…see “Guideline 3”.
GUIDELINE #2: A salt containing the conjugate acid of a _____________ base will produce an
__________________solution when dissolved in water.
Example:
Salt = ammonium chloride, NH4Cl(s)
*This salt contains the conjugate of what weak base?__________________
2 (l )
Dissociation equation: NH4Cl(s) 

H O
Hydrolysis equation:
**CONJUGATE BASES OF STRONG ACIDS (i.e. NO3-, SO42-, Cl-, I-, Br-) DO NOT react with
water. (Remember: Ka x Kb = Kw….very strong acids have very weak conjugates….see p. 209 of
text) If the conjugate is not one of these (i.e. NO3-, SO42-, Cl-, I-, Br- ), assume the anion reacts as a
weak base.
In general:
(i) Strong acids have very weak (i.e. DO NOT react with water) conjugate _________.
*(ii) Weak acids have weak (DO react with water) conjugate __________.
*(iii)Weak bases have weak (DO react with water) conjugate __________.
(iv) Strong bases have very weak (DO NOT react with water) conjugate _________.
GUIDELINE #3: Small, highly charged metal ions (e.g. Al3+(aq), Fe3+(aq), and Sn2+(aq) react with water
to produce _________________ solutions.
Example:
Salt = aluminum nitrate, Al(NO3)3(s)
2 (l )
Dissociation equation: Al(NO3)3(s) 

H O
Hydration (formation of hydrated complex ion):
Al3+(aq) + 6H2O(l)
Hydrolysis equation: Al(H2O)63+(aq) + H2O(l)
Extension:
*Hydrolysis of Amphoteric Ions:
Example: Baking soda, NaHCO3(s)
Dissociation:
2
NaHCO3(s) 


H O
Hydrolysis(2):
#1(acid hydrolysis):
HCO3-(aq) + H2O(l)
Ka =
HCO3-(aq) + H2O(l)
Kb =
and
#2(base hydrolysis):
*Net Effect  Acidic or Basic?
Kb _______ Ka, therefore, solution will be ___________ (i.e. pH > 7)
*Read 8.3 and answer section questions