1. Unit 3: Redox
Redox Reactions

2. Balancing Redox Equations Using Oxidation Numbers
In a balanced redox equation, the total increase in oxidation number of the element that is oxidized must equal the total decrease in oxidation number of the element that is reduced.
Procedure:
Assign oxidation numbers to all the atoms in the equation.
Identify which atoms undergo a change in oxidation number.
Determine the ratio in which these atoms must react so that the total increase in oxidation numbers equals the decrease.
Balance the redox participants in the equation.
Balance the other atoms by the inspection method

3. Example: Balance the following redox reaction
HNO H2S  NO S + H2O 1. 2. 3. 4. 5.

4. Example: Balance the following redox reaction
MnO4− + H2SO3 + H+  Mn2+ + HSO4− + H2O

5. Examples
I2 + HNO3  HIO3 + NO2 + H2O

6. b) HBr + HBrO3  Br2 + H2O

7. Balancing Using Oxidation #s Assign