The oxidation number of `S` in `H_(2)S_(2)O_(8)` is

Options

A. ` +7`
B. ` +4`
C. ` +6`
D. ` +2`

Answer

C

Explanation

According to the rules,
` 2(+1) =2x + 8 (-2) =0`
`2+2x - 16 =0`
`2x-14 =0`
` x= +7`
But the structure of ` H_2S_2O_8` is .
`H-O-underset(O)underset(||)overset(O)overset(||)(S)-O-O-underset(O)underset(||)overset(O)overset(||)(S)-O-H`
We can notice that it has a peroxide linkage `(O-O)` where the oxidation number of each O atom is ` -1`. Thus .
` 2( +1) + 2 x + 6(-2) + 2 (-1) =0`
` 2+ 2x -12 -2 =0`
` 2x -12=0`
` x= + 6`.