The oxidation number of sulfur in each of the following is +6 except a) s2o4^2- b) so3 c) na2so4 d) so4^2-

A

Explanation:

Oxygen always has a -2 oxidation state, sodium always has a +1 Oxidation state

A: 2(S) + 4(-2) = -2 (overall charge)

  2S -8 = -2

  2S = 6

  S = +3

B: S + -6 = 0 (overall charge)

   S = +6

C: 2(+1) + S + 4(-2) = 0 (overall charge)

   2 + S - 8 = 0

   S - 6 = 0

   S = 6

D: S + 4(-2) = -2 (overall charge)

   S - 8 = -2

   S = 6

it is the most commonly accepted one