Question

The sum of oxidation states of sulphur in $H_2{S}_2{O}_8$ is?

• A. $+2$
• B. $+6$
• C. $+7$
• D. $+12$

Answer 1

Answer: (D)

$+12$

Structure of $H_2{S}_2{O}_8$ is:

$HO-\stackrel{\stackrel{O}{||}}{\underset{\stackrel{||}{O}}{S}}-O-O-\stackrel{\stackrel{O}{||}}{\underset{\stackrel{||}{O}}{S}}-OH$

there is one peroxy linkage $S-O-O-S$. Hence two of the eight oxygen atoms have -1 oxidation state and rest 6 have -2 oxidation state. Let the total oxidation state of S be x

then $2\times 1+x+6\times (-2)+2\times (-1)=0$

or $2+x-12-2=0$

$x=+12$

Sum of oxidation state of both S is x i.e. 12 in $H_2{S}_2{O}_8$.