In the reaction 2H_2S+SO_2 -> 3S+2H_2O, what has been oxidized and what is the oxidizing agent?

Feb 10, 2017

Sulfide has been oxidized, and sulfur dioxide is the oxidizing agent.

Explanation:

This is an example of a comproportionation reaction in which sulfur compounds, in different oxidation states with respect to the sulfur, undergoes electron transfer to give a elemental sulfur (which is zerovalent).

$2 {H}_{2} S \rightarrow S + 2 {H}^{+} + 2 {e}^{-}$ $\left(i\right)$

(oxidation from $S \left(- I I\right)$ to $S \left(0\right)$)

$S {O}_{2} + 4 {H}^{+} + 4 {e}^{-} \rightarrow S + 2 {H}_{2} O$ $\left(i i\right)$

(reduction from $S \left(+ I V\right)$ to $S \left(0\right)$)

So $2 \times \left(i\right) + \left(i i\right)$ $=$ $2 {H}_{2} S + S {O}_{2} \rightarrow 3 S + 2 {H}_{2} O$