Copyright © 2008 Pearson
Prentice Hall, Inc.
Balancing Redox Reactions: The
Oxidation-Number Method
•Make the
total increase in oxidation number equal to the total decrease in oxidation number.
2Cr3+
I1-
(aq) +
O72-
(aq)
(aq) +
O31-
(aq)
I
+5
+3
Cr2
-1
+6
Net decrease = -6
Net increase = +6