Question

$K{O_2}$ (potassium superoxide) is used in oxygen cylinders in space and submarines because it:
(A) Produces ozone
(B) Absorbs $C{O_2}$
(C) Absorbs $C{O_2}$ and increases ${O_2}$ constants
(D) Eliminate moisture

Answer 1

Hint: To solve this question, we should know about superoxides. It is important to be aware of superoxides of alkali earth metals and its properties. Superoxide of alkali metals are widely used in oxygen cylinders etc.

Complete step by step answer:
Firstly we will see what superoxides are:
It is a type of oxides which contains superoxide ions ($O_2^ - $). The superoxide ion ($O_2^ - $) has a three electron bond. in this case the ion can be represented as:
              

The presence of one unpaired electron in three electron bonds makes this one paramagnetic in nature and coloured.
The alkali earth metals are lithium (Li), sodium (Na), potassium (K), Rubidium (Rb) and cesium (Cs). Lithium and sodium do not form superoxides, they form only peroxides. Superoxides of a potassium, rubidium and cesium are represented as $K{O_2}$, $Rb{O_2}$ and $Cs{O_2}$ respectively. Superoxides of alkali earth metals are a good oxidizing agent.
The stability of these superoxides is in the order: $K{O_2}$ < $Rb{O_2}$ < $Cs{O_2}$.

The potassium superoxide reacts with carbon dioxide and gives out potassium carbonate and oxygen.
\[K{O_2} + C{O_2}\xrightarrow{{}}{K_2}C{O_3} + {O_2}\]…………..Equation 1

Potassium peroxide is very sensitive to $C{O_2}$ so, there is an alternate reaction too.
\[K{O_2} + C{O_2} + {H_2}O\xrightarrow{{}}KHC{O_3} + {O_2}\]……………….Equation 2

From equation 1 and 2, it is evident that potassium superoxide absorbs $C{O_2}$ and gives out ${O_2}$.
So, the correct answer is “Option C”.

Note: From equation 1 and 2, It is evident that potassium superoxide has the ability of absorbing $C{O_2}$, this is due to its paramagnetic property. It gives out ${O_2}$ as a byproduct. The reaction in equation 1 takes place very fast and is almost quantitative. Potassium peroxide is used in space suits, oxygen cylinders used in space or submarines.