Question

Assertion: Oxygen atom in both, $O_{2}$ and $O_{3}$ has an oxidation number of $-2$.
Reason : Oxygen is assigned an oxidation number $-2$ in all of its compounds.

• A. If both assertion and reason are true and reason is the correct explanation of assertion.
• B. If both assertion and reason are true but reason is not the correct explanation of assertion.
• C. If assertion is true but reason is false.
• D. If both assertion and reason are false.

Answer 1

Answer: (D)

In elements, in the free state each atom bears an oxidation number of zero. Oxidation number of oxygen in most of its compounds is $-2$ with two exceptions : in peroxides, oxidation number of oxygen is $-1$ and in superoxides, oxidation number of oxygen is $-\frac{1}{2}$.