Chemistry - Redox Reactions Question with Solution | TestHub

To find the oxidation number of a given compound we have to equate the charge on the overall compound with the charge on individual atom of which the compound is made of. In ${\mathrm{KO}}_3.\mathrm{K}$ is an alkali metal. hence its oxidation number is $+1$. $(+1)+3\times (\mathrm{x})=0$ or $\mathrm{x}=\frac{-1}{3}\cong -0.33$ hence oxidation number of oxygen i.e. $x=-0.33$ In ${\mathrm{Na}}_2{\mathrm{O}}_2$, again $\mathrm{Na}$ is an alkali metal. Hence $2\times (+1)+2\times x=0$ $x=\frac{-2}{2}=-1$