How do I balance these equations? Please explain the half equations as well.
Fe2+ + MnO4- ----> Fe3+ + MnO2
H2O2 + Cr3+ ----> CrO42- + OH-
please help with redox balancing
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Re: please help with redox balancing
Split into half reactions, removing spectator ions and water and its ions.
Balance Oxygen using water. Balance Hydrogen using protons. Then balance the charges using electrons. Merge so that electrons cancel.
Note: To make alkaline, add sufficient on both sides to neutralise all (make water) and then cancel any water common to both sides.
Split in Half:
Balance O:
Balance H:
Balance e:
Merge:
Now you go:
Split in Half:
Balance O:
Balance H:
Alkalise:
Balance e:
Merge:
Balance Oxygen using water. Balance Hydrogen using protons. Then balance the charges using electrons. Merge so that electrons cancel.
Note: To make alkaline, add sufficient
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OH{-}
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H{+}
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Fe{2+} + MnO4{-} = Fe{3+} + MnO2
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Fe{2+} = Fe{3+} || MnO4{-} = MnO2
Balance O:
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Fe{2+} = Fe{3+} || MnO4{-} = MnO2 + 2 H2O
Balance H:
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Fe{2+} = Fe{3+} || MnO4{-} + 4 H{+} = MnO2 + 2 H2O
Balance e:
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3 Fe{2+} = 3 Fe{3+} + 3 e || MnO4{-} + 4 H{+} + 3 e = MnO2 + 2 H2O
Merge:
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3 Fe{2+} + MnO4{-} + 4 H{+} = 3 Fe{3+} + MnO2 + 2 H2O
Now you go:
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H2O2 + Cr{3+} = CrO4{2-} + OH{-}
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H2O2 = ? || Cr{+} = CrO4{3-}
Balance H:
Alkalise:
Balance e:
Merge: