Answer:
Oxidation state of S in SO3^2- is +4
Explanation:
S in SO3^2-=
S = ?
O = -2
S + 3 moles of O * -2 = -2
S + (-6) = -2( it has charge -2)
S - 6 = -2
S = -2 + 6
S = +4
Note, the sign is very important
Don't confuse SO3 together with SO3^2-, the oxidation state of S in SO3 is + 6, how?
S = ?
O = -2
S + 3 * -2 = 0 ( because it has no charge)
S - 6 = 0
S = +6
And in SO3^2-
S = +4
The difference is that one has charge SO3^2- and the other doesn't SO3.
