Question

How would you determine the oxidation number of Sulpher in `SO_3^-2`?

Answer 1

The oxidation state of sulfur in `SO_3^(2-)` is `+IV`.

Explanation:

The sum of the oxidation numbers/states of the individual elements in the species must equal the charge on the ion. `O` normally takes a `-II` oxidation state and it does here.

Thus `-2=3xx(-2)+ON_"sulfur"`

And so `ON_"sulfur"=-2+6=+4,` i.e. `+IV`.