Question

Which of the following is best ${\text{C}}{{\text{O}}_{\text{2}}}$ absorber as well as source of ${{\text{O}}_{\text{2}}}$ in space capsule?
A) ${\text{K}}{{\text{O}}_{\text{2}}}$
B) ${{\text{K}}_2}{{\text{O}}_{\text{2}}}$
C) ${\text{KOH}}$
D) ${\text{LiOH}}$

Answer 1

Carbon dioxide is absorbed in the alkali such as sodium hydroxide or potassium hydroxide.
Of the given species in the options, identify the one which gives oxygen and potassium hydroxide.

Complete step by step answer:
The Chemical formula ${\text{K}}{{\text{O}}_{\text{2}}}$ represents potassium superoxide. The Chemical formula ${{\text{K}}_2}{{\text{O}}_{\text{2}}}$ represents potassium peroxide. The Chemical formula ${\text{KOH}}$ represents potassium hydroxide. The Chemical formula ${\text{LiOH}}$ represents lithium hydroxide.
Potassium superoxide reacts with water to form potassium hydroxide and oxygen.
${\text{4K}}{{\text{O}}_{\text{2}}}{\text{ + 2}}{{\text{H}}_2}{\text{O }} \to 4{\text{KOH + 3}}{{\text{O}}_2}$
Potassium hydroxide absorbs carbon dioxide to form potassium hydrogen carbonate.
${\text{KOH + C}}{{\text{O}}_2}{\text{ }} \to {\text{KHC}}{{\text{O}}_3}$
Potassium superoxide ${\text{K}}{{\text{O}}_{\text{2}}}$ is best ${\text{C}}{{\text{O}}_{\text{2}}}$ absorber as well as source of ${{\text{O}}_{\text{2}}}$ in space capsule. Russian space agency had used potassium superoxide in chemical oxygen generators for spacesuits and spacecraft. Firefighters and mine rescue workers also use potassium superoxide. However, scuba rebreathers do not use potassium superoxide. This is because potassium superoxide reacts violently with water.
${\text{1 kg}}$ of potassium superoxide will absorb $0.310{\text{ kg}}$ of carbon dioxide and release $0.388{\text{ kg}}$ of oxygen.
${\text{1 mole}}$ of potassium superoxide will absorb ${\text{0}}{\text{.5 moles}}$ of carbon dioxide and release ${\text{0}}{\text{.75 moles}}$ of oxygen.

Hence, the option (A) is the correct option.

Additional Information: Potassium superoxide is yellow solid and paramagnetic in nature. In presence of moisture, it decomposes. Potassium superoxide contains potassium cation and superoxide anion. An ionic bond is formed between these ions.

Note: Potassium superoxide is formed by the reaction of molten potassium with oxygen.
${\text{K + }}{{\text{O}}_{\text{2}}}{\text{ }} \to {\text{ K}}{{\text{O}}_{\text{2}}}$
Potassium superoxide contains ${\text{O}}_2^ -$ ion.