Double Replacement
Objective: write double
replacement equations in
symbols with phase notation
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Double Replacement
Double Replacement reactions
typically
two ionic
Noticestart
it is CBwith
not BC!!
compounds
and form
All ionic compounds
must two
be written with
the
different
compounds
cation FIRST according
to Criss-Cross.
AB + CD 
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AD + CB
Double Replacement
Double Replacement reactants
are
typically
aqueous.
Individual
ions need
to
be free to move and
WHY??
associate with
different ions to form
new compounds
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Double Replacement
Double Replacement reactions
tend to produce:
1. Water
2. A gas and other compounds
3. A precipitate
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Neutralization: Producing Water
Neutralization: A double replacement
reaction between an acid and a base that
produces a salt and water
Acid- a compound with a hydrogen cation
Base- a compound with a hydroxide anion
Salt- a lattice compound formed when an
acid’s hydrogen is replaced with a metal
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Neutralization: Producing Water
hydrochloric acid is neutralized
with sodium hydroxide
HCl(aq) + NaOH(aq) 
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NaCl(aq) + H2O(l)
Neutralization: Producing Water
sulfuric acid is neutralized with
potassium hydroxide
H2SO4(aq) + KOH(aq)
 K2SO4 (aq) + H2O(l)
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Neutralization: Producing Water
acetic acid is neutralized with
ammonium hydroxide
HC2H3O2(aq) + NH4OH(aq)

NH4C2H3O2(aq) + H2O(l)
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Producing a Gas
When an ACID (compound) is
added to a CARBONATE or a
BICARBONATE containing
compound, carbon dioxide is
produced along with water and
one other compound.
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Producing a Gas
hydrochloric acid is added to solid
calcium carbonate
HCl(aq) + CaCO3(s)

CaCl2(aq) + CO2(g) + H2O(l)
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Producing a Gas
Nitric acid is added to solid sodium
bicarbonate
HNO3(aq) + NaHCO3(s)

NaNO3(aq) + CO2(g) +
H2O(l)
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Producing a Precipitate
Sometimes a double
replacement reaction results in
a compound that is not soluble
in water. This insoluble solid is
a precipitate.
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Solubility Rules
Soluble Ions
NH4+1 salts
Group 1A salts
NO3-1 salts
C2H3O2-1 salts
Chlorides, Bromides, and Iodides
SO4-2
HSO4-1
Notable Exceptions
None
None
None
none
Ag, Pb, Hg
Ba, Pb, Ca, Sr, Hg
none
Movie
Solubility Practice
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PRACTICE
a solution of potassium
iodide is added to a solution
of lead (II) nitrate
potassium iodide + lead (II) nitrate  potassium nitrate + lead (II) iodide
KI(aq) + Pb(NO3)2(aq)  KNO3(aq) + PbI2(ppt)
SOLUBILITY RULES:
•GROUP 1A COMPOUNDS ARE USUALLY AQUEOUS
•LEAD COMPOUNDS ARE USUALLY PRECIPITATES
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PRACTICE
a solution of potassium
carbonate is added to a solution
of nickel nitrate
potassium carbonate + nickel nitrate  potassium nitrate + nickel carbonate
K2CO3(aq) + Ni(NO3)2(aq)  KNO3(aq) + NiCO3(ppt)
SOLUBILITY RULES:
•GROUP 1A COMPOUNDS ARE USUALLY AQUEOUS
•NITRATES ARE USUALLY AQUEOUS
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•CARBONATES ARE USUALLY PRECIPITATES
PRACTICE
a solution of sodium hydroxide is
added to a solution of copper (II)
chloride
sodium hydroxide + copper (II) chloride  sodium chloride + copper (II) hydroxide
NaOH(aq) + CuCl2(aq)  NaCl(aq) + Cu(OH)2(ppt)
SOLUBILITY RULES:
•GROUP 1A COMPOUNDS ARE USUALLY AQUEOUS
•HYDROXIDES ARE USUALLY PRECIPITATES
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PRACTICE
a solution of sodium phosphate
is added to a solution of cobalt
(II) chloride
Sodium phosphate + cobalt (II) chloride  sodium chloride + cobalt (II) phosphate
Na3PO4(aq) + CoCl2(aq)  NaCl(aq) + Co3(PO4)2(ppt)
SOLUBILITY RULE:
GROUP 1A COMPOUNDS ARE USUALLY AQUEOUS
•PHOSPHATES ARE USUALLY PRECIPITATES
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PRACTICE
a solution of silver nitrate is
added to a solution of
hydrochloric acid
silver nitrate + hydrochloric acid silver chloride + nitric acid
AgNO3(aq) + HCl(aq)  AgCl(ppt) + HNO3(aq)
SOLUBILITY RULE:
•SILVER COMPOUNDS ARE USUALLY PRECIPITATES
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