Redox Reactions Ques 20
20. The oxidation states of sulphur in the anions $SO_3{ }^{2-}, S_2 O_4{ }^{2-}$ and $S_2 O_6{ }^{2-}$ follow the order
[2003]
(a) $S_2 O_6{ }^{2-}<S_2 O_4{ }^{2-}<SO_3{ }^{2-}$
(b) $S_2 O_4{ }^{2-}<SO_3{ }^{2-}<S_2 O_6{ }^{2-}$
(c) $SO_3{ }^{2-}<S_2 O_4{ }^{2-}<S_2 O_6{ }^{2-}$
(d) $S_2 O_4{ }^{2-}<S_2 O_6{ }^{2-}<SO_3{ }^{2-}$
Show Answer
Answer:
Correct Answer: 20.(b)
Solution:
- (b) $SO_3^{2-} \to S$ is in $+4$ oxidation state
$S_2 O_4^{2-} \to S$ is in $+3$ oxidation state
$S_2 O_6^{2-} \to S$ is in $+5$ oxidation state
The structure of $S_2 O_4{ }^{2-}$ and $S_2 O_6{ }^{2-}$ are symmetrical. Thus, both sulphur atoms are in same oxidation state. This is not the case with $S_2 O_3{ }^{2-}$ or $S_4 O_6{ }^{2-}$ ions.
BETA
