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DrBob222 ClO^-1 + CrO2^-1 = Cl^-1 + CrO4^-2
Break this into the two half equations and balance each.
ClO^- + 2e + 2H^+ ==> Cl^- + H2O
CrO2^- + 2H2O==> CrO4^2- + 3e + 4H^+
Now multiply eqn 1 by 3 and eqn 2 by 2 (which makes the electrons lost = electrons gained). Add the two resulting equations.You will see some common ions/electrons/etc and you want to cancel those.For example, you will see H^+ on both sides, H2O on both sides and you need to adjust so those appear only on one side. Check to see that it balances three ways and you're done. It must balance as follows:
1. Atoms on each side must be the same.
2. The charge on both sides must be the same.
3. The electrons gained must = the electrons lost.
Post your work if you get stuck.