The oxidation number of sulphur in sulphur dioxideSO2 and sulphuric acidH2SO4 is respectively
+4 and +6
Let us take a look at sulphur dioxide(SO2).
Let the oxidation number of sulphur in this compound be x.
Since there is no charge on this compound so the sum of oxidation number for all the elements is equal to zero.
x + (2)(-2) = 0
x = +4
Hence the oxidation number of sulphur is +4 in SO2.
Now let's take a look at sulphuric acid(H2SO4).
Let the oxidation number of sulphur in this compound be y.
2(1) + y + 4(-2) = 0
y -6 = 0
y = +6
Oxidation number of sulphur is +6 in H2SO4.
So the answer is +4 and +6.