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Topic: half reaction with bases  (Read 6515 times)

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Offline sparkly

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half reaction with bases
« on: April 08, 2009, 01:14:00 PM »
Use the half reaction method to write balanced ionic equations for each reaction. All are basic solutions!

a) MnO4-(aq) + ClO2-(aq) --> MnO2(s) + ClO4-(aq)
In our book they only give an example with acids. I can't make this balance
This is how far I got...

Write unbalanced reaction in ionic form

MnO4-(aq) + ClO2-(aq) --> Mn+4(aq) +O2-2(g) + ClO4-(aq)

Write separate half reactions

Oxidation half reaction ClO2-(aq) --> ClO4-(aq)

Reduction half reaction   MnO4-(aq) --> MnO2(s)
I'm not sure if this last half reaction should be MnO4-(aq) --> Mn4+
But either way when I try to balance it with H2O and OH... it WON"T balance!!!
Reduction half reaction   MnO4-(aq) --> MnO2(s)

MnO4-(aq) +2H2O (l)--> MnO2(s) + 4OH(aq)
everytime I add H2o it ads H, btu everytime I add Oh to balance the H, the O goes up....

 *delete me*!!!

Offline Borek

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Re: half reaction with bases
« Reply #1 on: April 08, 2009, 01:57:12 PM »
MnO4-(aq) +2H2O (l)--> MnO2(s) + 4OH(aq)

Charges are still wrong, but atoms look balanced to me.
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