Chapter 4 Revision : Writing Ionic Equation
Steps :
1. Balance the normal chemical equation (molecular equation) given.
For example: CaCl2(aq) + AgNO3(aq)  Ca(NO3)2 (aq) + AgCl (s)
Balanced: CaCl2(aq) + 2AgNO3(aq)  Ca(NO3)2 (aq) + 2AgCl (s)
2. i) Separate and write the corresponding aqueous state ions present in the
reaction. This is known as “total ionic equation”.
Ca2+ (aq) + 2Cl- (aq) + 2Ag+ (aq) + 2NO3- (aq)  Ca2+ (aq) + 2NO3- (aq) + 2AgCl(s)
Etc: NaOH(aq)
BaCl2(aq)
K2O (aq)
HCl (aq)
AgNO3(aq)
Na2SO4(aq)
=
=
=
=
=
=
Na+ + OHBa2+ + 2Cl2K+ + O2H+ + ClAg+ + NO32Na+ + SO42-
ii) If the substances are in solid, liquid and gas, just copy the whole thing
down.
Etc: AgCl (s)
BaSO4 (s)
H2O (l)
Br2 (l)
HCl (g)
Cl2 (g)
*CH3COOH(aq)
*NH3.H2O(aq)
=
=
=
=
=
=
=
=
AgCl
BaSO4
H2O
Br2
HCl
Cl2
CH3COOH ( not H+ & CH3COO-)
NH3.H2O ( not NH4+ & OH- )
3. Cancel out the spectate ions (same ions at both side) which are in aqueous
state. This is known as “net ionic equation”.
Ca2+ (aq) + 2Cl- (aq) + 2Ag+ (aq) + 2NO3- (aq)  Ca2+ (aq) + 2NO3- (aq) + 2AgCl(s)
Net ionic equation : 2Ag+ (aq) + 2Cl- (aq)  2AgCl(s)
4. Simplify the coefficient of net ionic equation whenever possible.
Completed ionic equation: Ag+ (aq) + Cl- (aq)  AgCl(s)
Practice:
1. Write the net ionic equation for following reactions:
a.) NaBr(aq)
+
AgNO3(aq)  NaNO3(aq) +
AgBr(s)
b.) BaCl2(aq)
+
Na2SO4(aq) 
BaSO4(s)
+
NaCl(aq)
c.) NaCl(aq)
+
Pb(NO3)2(aq) 
PbCl2(s)
+
NaNO3(aq)
d.) KOH(aq)
+
HCl(aq)

KCl(aq)
+
H2O(l)
e.) NaOH(aq)
+
H2SO4(aq)

Na2SO4(aq) +
H2O(l)
f.) CuO(s)
+
HCl(aq)

CuCl2(aq)
+
H2O(l)
g.) HCl(aq)
+
Al(OH)3(s)
 H2O(l)
+
AlCl3(aq)
i.) CuSO4(aq)
+
H2S(g)

+
H2SO4(aq)
CuS(s)
2. Write the net ionic equation for following reactions:
a.) Zn(s)
+
CuSO4(aq)  ZnSO4(aq) +
Cu(s)
b.) FeCl3(aq)
+
Mg(s)

MgCl2(aq) +
Fe(s)
c.) Cl2(g)
+
KBr(aq)

KCl(aq)
+
Br2(l)
d.) Ca(s)
+
HCl(aq)

CaCl2(aq)
+
H2(g)
e.) Na(s)
+
H2O(l)

NaOH(aq) +
H2(g)
3. Write the net ionic equation for following reactions:
a.) Na2CO3(aq)
+
HCl(aq)

NaCl(aq)
+
CO2(g)
+
H2O(l)
b.) BaCO3(s)
+
HCl(aq)

BaCl2(aq)
+
CO2(g)
+
H2O(l)
c.) MgSO3(s)
+
HCl(aq)

MgCl2(aq) +
SO2(g)
+
H2O(l)
d.) NH4Cl(aq)
+
Ba(OH)2(aq)  BaCl2(aq)
NH3(g)
+
H2O(l)
+
4. Write the net ionic equation for following reactions:
a.) CH3COOH(aq)
+
KOH(aq)
 CH3COOK(aq)
b.) CuSO4(aq)
+
NH3.H2O(aq)
 Cu(OH)2(s)
+
H2O
+
(NH4)2SO4(aq)