|Balancing Redox Equations by the
Method or Half Cell Method
|This method divides a reaction into two parts that are
separately. It provides a simple method for obtaining a net ionic
for a redox reaction.
|In this method the oxidation and reduction processes are
into separate equations called half-reactions that are balanced
Then the half reactions are combined to give the overall net ionic
|In many redox reaction in aqueous solution the H+ and
ions play an important role, as do the H2O
themselves. Because H+ and OH- can be consumed
produced by a redox reaction, and Because the products can change
a reaction if the solution changes from acidic to basic (or vice
redox reactions are generally carried out in solutions containing a
excess of either acid or base. Therefore, before you apply the
method, you have to know whether the reaction occurs in an acidic or
|In Acidic Solutions
|Step 1 Divide the skeleton equation into half-reactions.
|Step 2 Balance atoms other than H and O.
|Step 3 Balance oxygen atoms by adding H2O to
that needs O.
|Step 4 Balance hydrogen by adding H+ to the
|Step 5 Balance the charge by adding electrons.
|Step 6 Make the electrons gained equal to the electrons
then add the two half-reactions.
|Step 7 Cancel anything that is the same on both sides.
|In Basic Solutions
|Step 8 Add the same number of OH- as there are
sides of the equation.
|Step 9 Combine OH- and H+ to form H2O
|Step 10 Cancel any H2O that you can.