Answer:
Explanation:
Oxidation number of Na = 1+ There are two of them, so it is 2*1 = 2
Oxidation number of O = 2- There are 6 of them so 6 * 2- = -12
There are 4 S's so the oxidation number is 4*S
Now set up a small equation
2 + 4s - 12 = 0
And solve.
2 - 12 + 4s =0
-10 + 4s = 0
4s = 10
4s/4 =10/4
s = 2.5
