Chemistry - Redox Reactions Question with Solution | TestHub

In ${\text{KO}}_2$, potassium is an alkali metal, so its oxidation state is always $+1$.

In ${\text{H}}_2{\text{O}}_2$, oxygen is present as a peroxide ion (${\text{O}}_2^{2-}$), so the oxidation state of oxygen is $-1$.

In ${\text{H}}_2{\text{SO}}_4$, let the oxidation state of sulfur be $x$.

$2(+1)+x+4(-2)=0$

$x-6=0$

$x=+6$

The oxidation states of the underlined elements are $+1,-1$ and $+6$ respectively.

Answer: $+1,-1$ and $+6$