Question

What is the sum of oxidation numbers of oxygen and hydrogen in $O_2$ and $H_2$ respectively?

• A. $-1$
• B. $0$
• C. Can't be predicted
• D. $+2$

Answer 1

The correct option is B $0$

We know,
The oxidation number of an element in its elementary form or uncombined state is zero.
Here, $O_2$ and $H_2$ are elementary states of oxygen and hydrogen so their oxidation no. is $0$ and $0$ in $O_2$ and $H_2$ respectively.
So, sum of oxidatoin numbers $=0+0=0$.