Question: Oxidation number of potassium in $\mathrm{K}_{2} \mathrm{O}, \mathrm{K}_{2} \mathrm{O}_{2}$ and $\mathrm{KO}_{2}$, respectively, is :
$+1,+4$ and $+2$
$+1,+2$ and $+4$
$+1,+1$ and $+1$
$+2,+1$ and $+\frac{1}{2}$
Correct Option: , 3
Solution:
Potasisum has an oxidation of $+1$ (only) in combined state.
