How to Balance this Equation by Oxidation number method? #H_2SO_4+HI->H_2O+H_2S+I_2#
And of course sulfide anion has the same oxidation state as the charge on the ion, i.e.
And for every reduction there is a corresponding oxidation......
And we takes
The which, I think, is balanced with respect to mass and charge; as indeed it must be if it is to represent physical reality.