balancing half reactions: ClO2^-1 --> Cl^-1

2 answers

please can anyone answer this question.. i would really appreciate it :)
http://www.chemteam.info/Redox/Redox.html
Is this an acid solution?
ClO2^- ==> Cl^-
1.
Cl changes from +3 to -1; we balance the change with electrons.
ClO2^- + 4e ==> Cl^-

2.
Count up charge on each side and balance with H^+ (if in acid soln or with OH^- of basic solution).
Charge on left is -5; on right is -1

3.
ClO2^- + 4e + 4H^+ ==> Cl^-

4.
Add H2O to balance the H and O.
ClO2^- 4e + 4H^+ ==> Cl^- + 2H2O

5. Check it.
a.for atoms.
1Cl on left and right.
2 O on left and right.
4H on left and right.
b. for charge.
-1 on left; -1 on right
c. for change in oxidation state.
Change from +3 + 4e = -1
All ok.