Ionic equations

Ionic reactions show only the ions that react and the products that form.

Lets take the reaction between solutions of silver nitrate and sodium chloride. A white precipitate of silver chloride forms.(Click to see a 120kb movie).
The overall equation for this reaction is shown below.


AgNO3(aq) + NaCl(aq) => AgCl(s) + NaNO3(aq)

But the Na+ and NO3- ions do not take part in the reaction. There are free sodium and nitrate ions floating in solution before and after the reaction. The ions that do not take part in the reaction are called spectator ions.

The only ions reacting to form a new product are the Ag+ and Cl- ions. The new product formed is solid silver chloride (AgCl).

So the balanced ionic equation for this reaction is given below

Ag+(aq) + Cl-(aq) => AgCl(s)

Click to see an animated explanation of the process above.

Example . Write the ionic equation for the reaction that occurs between solutions of magnesium sulfate and sodium sulfide.
Step 1 Write the balanced overall equation, as outlined previously.

MgSO4(aq) + Na2S(aq) => MgS(s) + Na2SO4(aq)

 

Mg2+(aq) + SO42-(aq) + 2Na+(aq) + S2-(aq) => MgS(s) + 2Na+(aq) + SO42-(aq)

Step 3 Delete from the equation the spectator ions.to obtain the balanced ionic equation for this reaction.

Mg2+(aq) + S2-(aq) => MgS(s)

Write ionic equations for the following

a) Copper(II) sulfate and sodium carbonate (Solution)
b) Ammonium phosphate and zinc sulfate (Solution)
c) Sodium hydroxide and iron(III) nitrate (Solution)
d) Potassium sulfide and aluminium chloride
e) Sodium carbonate and calcium nitrate
f) Silver nitrate and sodium chromate
g) Barium nitrate and copper sulfate
h) Sodium hydroxide and copper sulfate
i) Lead(II) nitrate and sodium chromate
j) Silver nitrate and potassium iodide
k) Calcium nitrate and ammonium phosphate
l) Lead(II) nitrate and sodium carbonate
m) Silver nitrate and sodium sulfide
n) Nickel(II) nitrate and sodium hydroxide.
o) Barium nitrate and potassium chromate

p) sodium hydroxide and hydrochloric acid

Click to see the chart of common ions

 

Solutions