Question

Balance the following equation in Basic medium

Answer 1

I am not sure of the answer, but I did like this:

1) Half-reactions and balancing:

     Cl2 O7  +  H2O  ==>  2 ClO2^-  + 2 H^+  + 2 O2        No free electrons.

     Balancing:

  2a Cl2O7 + 2b H2O ==> 4a ClO2^-  + 4b H^+  + (3a+b) O2 + (4b - 4a) e^-

     7a + b = 4a+ 2c    => 2c = 3a+b

     2 H^- + 2 H2O2 => 2 H2O + O2 + 2 H^+ , no free e^-, H+ helps reaction

2) Basic medium with OH^- ions:

     2 OH^- +  Cl2 O7   ==>  2 ClO2^-   + 2 O2  +   H2O,    no free  e^-.

     2 H2O2 + 2 H2O  => 2 H2O + O2  +  2 H^+  + 2 OH^-        no free e^-

3) Summing up:

  ClO7 (g) + 2 H2O2(aq)  <==> 2 ClO2^- (aq) + 3 O2 (g) + 2 H^+  + H2O

OR,

  ClO7 (g) + 2 H2O2(aq) <==> 2 ClO2^- (aq) + 3 O2 (g) + 3 H^+  + OH^-