[Seons R]

I just had a lab preparing Sodium Peroxoborate and I am stuck on two of the equations that are required for the Qualitative tests. I have made out two equations but I'm not sure if they are correct and whether or not they require half-reactions as well as the net-equation itself.

First off, The procedure for the Qualitative tests was as follows:
- Take about 0.1g of dry Na₂[B₂(O₂)₂(OH)₄].6H₂O and dissolve it in water making up the solution to 10mL. To 5mL of the fresh solution
(a) Add 1M sulfuric acid and then add 0.02M K[MnO₄] solution dropwise.
(b) Add 1M sulfuric acid and then add 10% w/v potassium iodide solution dropwise.

Now the equations I came up with are as follows:

(a) Na₂[B₂(O₂)₂(OH)₄].6H₂O + H₂SO₄  + KMnO₄ --> Na₂[B₂(O₂)₂(OH)₄].6H₂O + Mn²⁺ + 4H₂O

(b) Na₂[B₂(O₂)₂(OH)₄].6H₂O + H₂SO₄ + KI₂ --> Na₂[B₂(O₂)₂(OH)₄].6H₂O + 2I^- + [S₂O₆]^2-

This is my next problem, if the above equations are correct but require half equations also, I can only come up with one half equation each for both (a) and (b).
If half equations are required then for (a) one half equation would be
MnO_4^- + 5e^- + 8H⁺ --> Mn²⁺ + 4H₂O
However I do not know what the other half equation could be as I do not think Sulfuric Acid is involved except in order to catalyse the rxn?

Also, for (b) I Think that one half equation could be KI₂ + 2[S₂O₃]^2- --> 2I^- + 2[S₄O₆]^2-
However, as above I just can't fathom what the other half equation could possibly be for similar reasons..

If someone could tell me whether half equations are needed/my attempts thus far are correct/incorrect and give me some much needed insight I would be much obliged as I only have a few days to complete the report. Thanks very much!

[Borek]

Your attempts don't make much sense, as Na₂[B₂(O₂)₂(OH)₄]·6H₂O is just a spectator - you can safely cancel it out from both equations and nothing will change.

No idea what the first reaction is about. Peroxoboarte is - as the name implies - an oxidizer, so when mixed with iodide (BTW, formula of iodide is not KI₂) it can oxidize iodide to iodine.

No idea where you got thiosulfate from. Your solutions never contained it and sulfuric acid won't automagically turn into thiosulfate.