Question

The oxidation number of oxygen in hydrogen peroxide is:

• A. $+1$
• B. $-1$
• C. $+2$
• D. $-2$

Answer 1

The correct option is B $-1$

Molecular formula of hydrogen peroxide is $H_2{O}_2$.

The oxidation number of H is +1, but it is -1 in when combined with less electronegative elements.

Since oxygen is more electronegative than hydrogen, therefore oxidation no. of hydrogen in $H_2{O}_2$ will be +1.

Let the oxidation no. of oxygen in $H_2{O}_2$ be x.

As we know that, the sum of the oxidation numbers of all the atoms in a neutral compound is 0.

$\therefore (x\times 2)+((+1)\times 2)=0$

$\Rightarrow 2x+2=0$

$\Rightarrow x=-1$

Hence, the oxidation no. of oxygen in hydrogen peroxide is -1.