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Balance the redox reaction and identify what are the oxidizing and reducing agents H2O2...

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spock1 | Student, Undergraduate | Honors

Posted April 25, 2013 at 11:17 AM via web

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Balance the redox reaction and identify what are the oxidizing and reducing agents

H2O2 + MnO4- ---> Mn2+ + O2 (g)   <acidic>

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jerichorayel | College Teacher | (Level 1) Senior Educator

Posted April 25, 2013 at 4:06 PM (Answer #2)

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First we need to know which species got oxidized and reduced.

Reduction:

`MnO_4^(-) -> Mn^(2+)`

`MnO_4^(-) -> Mn^(2+) + 4H_2O`

`8 H^(+) + MnO_4^(-) -> Mn^(2+) + 4H_2O`

`5 e^(-) + 8 H^(+) + MnO_4^(-) -> Mn^(2+) + 4H_2O` -> equation 1

 

 

Oxidation:

`H_2O_2 -> O_2`

`H_2O_2 -> O_2 + 2H^+`

`H_2O_2 -> O_2 + 2H^+ + 2 e^(-)`

 

 

Balance the electrons by multiplying the equation 2 by 5 and the equation 1 by 2:

`(H_2O_2 -> O_2 + 2H^+ + e^- ) * 5`

`5 H_2O_2 -> 5 O_2 + 5 2H^+ + 10 e^-`

 

`( 5 e^(-) + 8 H^(+) + MnO_4^(-) -> Mn^(2+) + 4H_2O ) * 2`

`10 e^(-) + 16 H^(+) + 2 MnO_4^(-) -> 2 Mn^(2+) + 8 H_2O`

 

Combine the two resulting equation:

                `5 H_2O_2 -> 5 O_2 + 10 H^+ + 10 e^-`

 `10 e^- + 16 H^(+) + 2 MnO_4^(-) -> 2 Mn^(2+) + 8 H_2O`
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`5 H_2O_2 + 6H^(+) + 2MnO_4^(-) ->2 Mn^(2+) +5 O_2 +8 H_2O`

 

 

 

 

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