The oxidation states of S atom in `S_(4)O_(6)^(2-)` from left to right respectively are
`O-underset(O)underset(||)overset(O)overset(||)S-S-S-underset(O)underset(||)overset(O)overset(||)S-O`

Options

A. `+6,0,0,+6`
B. `+3,1,+1,+3`
C. `+5,0,0,+5`
D. `+4,+1,+1,+4`

Answer

C

Explanation

Two of the sulphur atoms are present in the oxidation state of zero and two are in oxidation state +5.
the structure of `S_(4)O_(6)^(2-)`.
`.^(-)O-underset(O^(-2))underset(||)overset(O^(-2))overset(||+5)(S)-overset(0)(S)-overset(0)(S)-underset(O^(-2))underset(||)overset(O^(-2))overset(||+5)(S)-O^(-)`
Since, each of the terminal sulphur atoms is connected to two oxygen atoms by a double bond and to one oxygen atom by a single bond, the oxidation state of these terminal sulphur atoms are linked to each other by a single bond and each other by a single bond and each sulphur is further attached to similar species on either side, the electron pair forming S-S bond remains in the centre and hence, each of the two central sulphur atoms has an oxidation state of zero. thus, the average oxidation state of zero. thus, the average oxidation state of the four sulphur atoms is `(2xx5+2xx0)//4=2.5`
Middle S-atoms has 0 oxidation number.