Question

What is the oxidation number of oxygen in ${\text{K}}_2\text{O}$?
(Oxidation number of potassium is +1)

• A. -2

Answer 1

The correct option is A -2
The given compound is an ionic compound which is made up of two potassium and one oxygen atoms.

Oxidation number of K = +1.
Let us assume that the oxidation number of oxygen in ${\text{K}}_2\text{O}$ is $x$.

The sum of oxidation numbers of all the elements in a neutral compound is equal to zero.

So, if we take the sum of oxidation numbers of the elements in ${\text{K}}_2\text{O}$ , we get the equation:

2$\times$(K)+ (O) = $0$

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

2 + ($x$) = $0$

Hence, $x$ = - 2.