Balancing Net Ionic Equations
1. Identify nature of the compounds involved.
2. Determine which reactant compounds and ions are really in the solution:
a. Soluble ionic compounds are strong electrolytes; they ionize when they dissolve.
b. Insoluble ionic compounds do not dissolve and do not ionize. They will appear
in the solid state.
c. Strong acids and bases ionize when they are dissolved in water.
d. Weak acids and bases do NOT ionize when they are dissolved in water. They will
appear in the aqueous state.
3. Determine the nature of the cross-combinations (put the cations with new anions).
4. Determine which product ions and compounds are really in the solution:
a. Soluble ionic compounds are strong electrolytes. They ionize when they
dissolve.
b. Insoluble ionic compounds do not dissolve and do not ionize. They will appear
in the solid state.
c. Strong acids and bases ionize when they are dissolved in water.
d. Weak acids and bases do NOT ionize when they are dissolved in water. They will
appear in the aqueous state.
5. Determine ions that have not changed (called spectator ions).
6. Write an equation that excludes spectator ions.
7. Balance that equation.
Balancing Net Ionic Equations
1. Identify nature of the compounds involved.
ex: Pb(NO3)2 (aq) + HCl (aq)  ?
Pb(NO3)2 (aq) is a soluble ionic compound (Table 4.2 page 119 in Chang and HCl (aq) is a
strong acid (Table 4.1 page 117 in Chang). The symbol (aq) indicates that they are both
dissolved in water.
2. Determine which reactant compounds and ions are really in the solution:
a. Soluble ionic compounds are strong electrolytes; they ionize when they dissolve.
ex: Pb(NO3)2 is composed of lead ion (Pb2+) and nitrate ion (NO3-)
b. Insoluble ionic compounds do not dissolve and do not ionize. They will appear
in the solid state.
c. Strong acids and bases ionize when they are dissolved in water.
ex: HCl ionizes into hydrogen ion (H+) and chloride ion (Cl-)
d. Weak acids and bases do NOT ionize when they are dissolved in water. They will
appear in the aqueous state.
ex: before the reaction, the solution contains these four reactants: Pb 2+, NO3-, H+, Cl3. Determine the nature of the cross-combinations (put the cations with new anions).
ex: looking at lead chloride (PbCl2, the combination of Pb2+and Cl-) we find that it is an
insoluble ionic compound (Exception to rule in Table 4.2), and nitric acid (HNO3, the combination
of NO3- and H+), a strong acid (Table 4.1 page 117 in Chang).
4. Determine which product ions and compounds are really in the solution:
a. Soluble ionic compounds are strong electrolytes. They ionize when they
dissolve.
b. Insoluble ionic compounds do not dissolve and do not ionize. They will appear
in the solid state.
ex: PbCl2 product is really PbCl2 (s).
c. Strong acids and bases ionize when they are dissolved in water.
ex: HNO3 is really H+ and NO3-.
d. Weak acids and bases do NOT ionize when they are dissolved in water. They will
appear in the aqueous state.
ex: after the reaction, three products: PbCl2 (s), H+ and NO35. Determine ions that have not changed (called spectator ions). ex:
6. Write an equation that excludes spectator ions.
ex: Pb2+ + Cl-  PbCl2 (s)
7. Balance that equation.
ex: Pb2+ + 2 Cl-  PbCl2 (s)
H+ and NO3-