Question

In the reaction $2Ba{O}_2\to 2BaO+O_2$, the oxidation number of barium

• A. decreases from $+4$ to $+2$
• B. decreases from $+2$ to $0$
• C. increases from $-4$ to $-2$
• D. does not change

Answer 1

The correct option is D does not change

The oxidation number of barium in barium peroxide and barium oxide remains the same, which is $+2$. The oxidation number of oxygen changes. In barium peroxide, it is $-1$, whereas in barium oxide, it is $-2$ and in oxygen, it is $0$.