Question

Which of the following compound contains the peroxy linkage?

• A. $H_2{S}_2{O}_8$
• B. $H_2{S}_2{O}_4$
• C. $H_2{S}_2{O}_6$
• D. None of these.

Answer 1

The correct option is A $H_2{S}_2{O}_8$

The compound contains a peroxy linkage when:
Calculated oxidation state is more the maximum oxidation state possible.

(a) $H_2{S}_2{O}_8$
Let oxidation state of Sulphur be $x$.
$\Rightarrow 2x+2\times (+1)+8\times (-2)=0$
$\Rightarrow x=+7$
calcualted O.S.$=+7$.
while maximum O.S. possible for sulphur is +6 so, $H_2{S}_2{O}_8$ contains a peroxy linkage.
The structure of $H_2{S}_2{O}_8$,




(b) $H_2{S}_2{O}_4$
Let oxidation state of Sulphur be $x$.
$\Rightarrow 2x+2\times (+1)+4\times (-2)=0$
$\Rightarrow x=+3$
calcualted O.S.$=+3$.
while maximum O.S. possible for sulphur is +6 so, $H_2{S}_2{O}_4$ does not contains a peroxy linkage.
The structure of $H_2{S}_2{O}_4$,




(c) $H_2{S}_2{O}_6$
Let oxidation state of Sulphur be $x$.
$\Rightarrow 2x+2\times (+1)+6\times (-2)=0$
$\Rightarrow x=+5$
calcualted O.S.$=+5$.
while maximum O.S. possible for sulphur is +6 so, $H_2{S}_2{O}_6$ does not contains a peroxy linkage.

The structure of $H_2{S}_2{O}_6$,



(a) is the correct answer.