The correct option is A S8<S2O2−3<S4O2−6<S2O2−8
For S8, as sulfur is present in its elemental state. So, oxidation number (O.N.) of S=0.
For S2O2−8
Here 2 oxygen have peroxide linkage so they will be having oxidation number -1, while other 6 will be having -2.
let oxidation number of S is x,
⇒2x+6×(−2)+2×(−1)=−2
⇒x=6.
For S2O2−3
Here all oxygen have oxidation number -2.
let oxidation number of S is y,
⇒2y+3×(−2)=−2
⇒y=2.
For S4O2−6
Here all oxygen have oxidation number -2.
let oxidation number of S is z,
⇒4z+6×(−2)=−2
⇒z=2.5.
The oxidation numbers of S are shown below along with the compounds:
S80,S2O2−8+6,S2O2−3+2,S4O2−6+2.5.
Hence the order of increasing O.N. of S is S8<S2O2−3<S4O2−6<S2O2−8.