How to Balance this Equation by Oxidation number method? H_2SO_4+HI->H_2O+H_2S+I_2

1 Answer
Jun 17, 2017

Well, "sulfur(VI+)" is REDUCED to S"(-II)"......

Explanation:

Well, "sulfur(VI+)" is REDUCED to S"(-II)"......a formal 8 electron transfer.......

"SO"_4^(2-)+8H^(+) +8e^(-) rarrS^(2-)+4H_2O(l) (i)

And of course sulfide anion has the same oxidation state as the charge on the ion, i.e. S(-II); a formal eight electron reduction.

And for every reduction there is a corresponding oxidation......

I^(-) rarr 1/2stackrel(0)I_2(s)+e^(-) (ii)

And we takes (i)+8xx(ii):

8I^(-) +SO_4^(2-)+8H^(+) rarr 4stackrel(0)I_2(s) +S^(2-) + 4H_2O(l)

The which, I think, is balanced with respect to mass and charge; as indeed it must be if it is to represent physical reality.