Which of the following has the central atom with the lowest oxidation number?
a. CO32-
b. NO3-
c. ClO2-
d. SO42-
e. PO43-
If you don't know how to determine oxidation numbers you will have a tough time balancing redox equations. Here is a good site.
http://dbhs.wvusd.k12.ca.us/webdocs/Redox/Redox-Rules.html
