Four sulfur oxyanions are given: thiosulfate S2O3^2-, dithionite S2O4^2-, dithionate S2O6^2- and disulfate S2O7^2- (none contains a peroxo link; O is -2). Which option lists them in INCREASING order of the (average) oxidation number of sulfur?

disulfate, dithionate, dithionite, thiosulfate

thiosulfate, dithionite, disulfate, dithionate

dithionite, thiosulfate, dithionate, disulfate

JEE Advanced levelSingle correct optionDifficulty 3 of 3bn036

Four sulfur oxyanions are given: thiosulfate $S X_{2} O X_{3} X^{2 -}$ , dithionite $S X_{2} O X_{4} X^{2 -}$ , dithionate $S X_{2} O X_{6} X^{2 -}$ and disulfate $S X_{2} O X_{7} X^{2 -}$ (none contains a peroxo link; O is $- 2$ ). Which option lists them in INCREASING order of the (average) oxidation number of sulfur?

Using

2 x + n (- 2) = - 2

S X_{2} O X_{3} X^{2 -}

gives

+ 2

S X_{2} O X_{4} X^{2 -}

gives

+ 3

S X_{2} O X_{6} X^{2 -}

gives

+ 5

S X_{2} O X_{7} X^{2 -}

gives

+ 6

. So the increasing order is thiosulfate, dithionite, dithionate, disulfate.