Redox Reaction
There are a set of half-reactions which students need to know;
H2O2 + 2H+ + 2e- ----> 2H2O
MnO4- + 8H+ + 5e-
----> Mn2+ + 4H2O
Cr2O72- + 14H+ +
6e- ----> 2Cr3+ + 7H2O
MnO2 + 4H+ + 2e- ----> Mn2+
+ 4H2O
O2 + 4H+ + 4e- ----> 2H2O
NO3- + 4H+ + 3e-
----> NO + 2H2O
SO42- + 4H+ + 2e-
----> SO2 + 2H2O
2H2O + 2e- ----> H2 + OH-
Do not forget the table of standard reduction potentials included
in the exam. It does not happen everytime, but that table often yields half
reactions for part if not for a complete equation in Problem 4.