This document discusses insoluble salts. It defines insoluble salts as salts that cannot dissolve in water at room temperature. It explains that insoluble salts can be prepared through precipitation reactions or double decomposition reactions by mixing aqueous solutions containing the cations and anions that will form the insoluble salt. This causes the ions to interchange and form an insoluble precipitate. Examples of insoluble salts formed and their ionic equations are also provided.

1. Salt

2. Solubility
of salt

3. Preparation of Insoluble salt.

4. Silver Chloride
Lead(II) Iodide

6. Outline
1. Definition
2. Preparation of Insoluble
Salts
3. Example of Insoluble Salts

7. Definition
• Solubility of a salt is usually
tested by dissolving a little bit of
the salt in distilled water.
• Salts that cannot dissolve in
water at the room temperature
(27oC) are called insoluble
salts.

8. Preparation of Insoluble
Salts
Insoluble salts can be prepared
through precipitation method
or double decomposition
reactions.

9. Precipitation method / Double
Decomposition reactions
Two aquoues solutions/soluble salts
were mix together
One of the solutions contains the
cations of the insoluble salt.
One of the solutions contains the
anions of the insoluble salt.

10. The ions of the two aqueous solutions
above interchange to produce two
new compound which is insoluble
salt or precipitate, and aqueous
solution.
The precipitate produced is obtained
by filtration. The residue left in the
filter paper is the insoluble salt. The
filtrate is soluble salt.
…continue

11. The residue/precipitate (insoluble
salt) then rinsed with distilled water to
remove any other ions as impurities.
Anion
(Non-metal ion)
Cation
(Metal ion) n
n m
m
Chemical : MX(aq) + NY(aq) → MY(s) + NX(aq)
equation solution solution precipitate solution
Ionic : M+(aq) + Y-(aq) → MY(s)
equation
…continue

12. Ionic precipitation of Lead(II) Chloride
Na+ Na+
NO3
-
NO3
-
PbCl2
Pb2+ ions combined
with Cl- ions to form
white precipitate
Na+ ions and NO3
- ions
do not take part in the
reaction and are free to
move in the solution
Ionic equation : Pb2+ + 2Cl-  PbCl2
Pb(NO3)2 solution
(supplies the
cation)
NaCl solution
(supplies the
anion)

13. Glass rod
PbCl2 salt
(the residue/precipitate)
NaNO3 solution
Mixture of solutions
Pb(NO3)2 + NaCl
Filter funnel
Filter paper
Retort stand
…continue

14. Glass rod
Distilled water
Precipitate of
lead(II) chloride
Retort stand
…continue

15. In the formation of the precipitate of
lead(II) chloride, PbCl2, the chemical
equation can be written:
Pb(NO3)2 (aq) + NaCl (aq)  PbCl2(s) + NaNO3 (aq)
Pb2+ + NO3- + Na+ + Cl -  PbCl2 + Na+ + NO3-
Ionic equation : Pb2+ (aq) + Cl - (aq)  PbCl2 (s)
Chemical and ionic equations
…continue

16. Example of the Insoluble
Salts
Insoluble Salt Ions Ionic equation
ZnCO3 Zn2+ , CO3
2- Zn2+ + CO3
2-  ZnCO3
AgCl Ag+ , Cl- Ag+ + Cl-  AgCl
BaSO4 Ba2+ , SO4
2- Ba2+ + SO4
2  BaSO4
PbCl2 Pb2+ , Cl- Pb2+ + Cl-  PbCl2
PbSO4 Pb2+ , SO4
2- Pb2+ + SO4
2-  PbSO4
CaCO3 Ca2+ , CO3
2- Ca2+ + CO3
2-  CaCO3

17. Exercise
 Refer to handout Exercise 1.
Complete the mind map
handout.