Which of the following has//have been arranged in order of decreasing oxidation number of sulphur?

Options

A. `Na_(2)S_(4)O_(6) gt H_(2)S_(2)O_(7) gt Na_(2)S_(2)O_(3) gt S_(8)`
B. `H_(2)SO_(4)gt SO_(2) gt H_(2)S gt H_(2)S_(2)O_(8)`
C. `SO_(2) gt SO_(4)^(2-) gt SO_(3)^(2-) gt HSO_(4)^(-)`
D. `H_(2)SO_(5) gt H_(2)SO_(3) gt SCl_(2) gt H_(2)S`

Answer

D

Explanation

O.N of S in `H_(2)S_(2)O_(5)` (Permonosulphuric acid)
`{:(" "-2),(" O"),("+1 -2 || -1 -1 +1"),(H-O-S-O-O-H),(" ||"),(" O"),(" "-2):}`
Let O.N of S = x
`:. 2(+1)+3(-2)+2(-1)+x=0`
`rArrx=6`
O.N of S in `H_(2)SO_(3)` :
Let O.N. of S = x
`:. 2(+1)+x+3(-2)=0`
`rArrx=4`
O.Nof S in `SCl_(2)` :
Let O.N of S =x
`:. x+2(-1)=0`
`rArr x=2`
O.N of S in `H_(2)S` :
Let O.N of S = x
`:. 2(+1)+x=0rArrx=-2`
`:.` decreasing order of O.N is
`H_(2)S_(2)O_(5)gtH_(2)SO_(3)gtSCl_(2)gtH_(2)O`