Why does thiosulfate oxidize to sulfate in an acidic medium?
Presumably because oxidation to sulfate (
Sodium thiosulfate is known to undergo disproportionation in acidified aqueous solution:
Now this is a balanced chemical equation, but the equation should conform to reality, not vice versa. Under these conditions, I presume, that oxidation to
Note that I presume that sulphur dioxide
So I would presume that the answer your question is that under these conditions oxidation of sulfur to sulfate is the thermodynamic outcome.