Question

Oxidation state of sulphur in sodium tetrathionate $\left(N{a}_2{S}_4{O}_6\right)$ is

• A. $+2$
• B. $+4$
• C. $+1.5$
• D. $+2.5$

Answer 1

The correct option is D $+2.5$

Let $x$ be the oxidation state of sulfur in sodium tetrathionate $\left(N{a}_2{S}_4{O}_6\right)$. The oxidation states of sodium and oxygen are $+1$ and $-2$ respectively.
In a neutral molecule, the sum of all the oxidation states should be zero.
Hence, $2\left(1\right)+4\left(x\right)+6(-2)=0$
or, $x=2.5$