Balancing Redox Equations: Half Reaction Method

[Soaring Crane]

I have been staring at the following problem, and I can't seem to get the correct answer. I tried using half reactions and the oxidation number method, but I don't know which works best.

Write balance net ionic equations for reaction in acidic solution.

ClO3- (aq) + As2S3 (s) --> Cl- (aq) + H2AsO4- (aq) + HSO4- (aq)

For the half reaction method, which 2 reactions do I divide this into?
I tried this way,

ClO3- --> Cl-
As2S3 --> H2AsO4- + HSO4-

but I suppose this is wrong.

Any help, especially with the half reaction method, is welcome and needed.

 

[Soaring Crane]

Any volunteers?

Thanks again.

 

[Astronuc]

It would seem one needs H⁺ or H₃O⁺ to balance the equation.

The number of atoms must be the same on both sides.

Also on could use H₂O also, as in CaO + H₂O -> Ca(OH)₂