Question

What is the oxidation state of K in $\text{K}{\text{O}}_2$ ?
Options-
(A) - 1
(B) - 2
(C) + 1
(D) 0

Answer 1

Hint: An attempt to this question can be made by drawing the expanded structure of the compound. Determine the oxidation state of atoms attached with Fe atoms in the compound. Based on that, determine the oxidation state of iron atoms such that the overall electric charge on the compound cancels out making the compound electrically neutral.

Complete answer:
Potassium superoxide is an inorganic compound which is paramagnetic in nature. It is yellow in colour and easily decomposes in air.
It is one of the few examples of stable superoxide. Potassium superoxide is commonly used as:
- $\text{C}{\text{O}}_2$ scrubber
- ${\text{H}}_2\text{O}$ dehumidifier
- ${\text{O}}_2$ generator in rebreathers, submarines, spacecraft and spacesuit systems.
We will now draw the structure of potassium superoxide.

In the structure given above we see that two oxygen atoms are attached to one potassium atom. In superoxide, the oxidation state of oxygen is - 1/2.
So, the total negative charge is 2 x (- 1/2) = -1.
So, the charge on potassium ion is + 1 making the oxidation state of potassium atom in potassium superoxide as + 1.

Therefore, the correct answer is + 1.i.e, Option C.

Note:
It is important to know that potassium superoxide is an ionic compound. The structure given in the solution is for reference purposes to calculate the oxidation state of potassium only. In solution, it exists as $K^{+}$ and ${O_2}^{-}$ ions only.