Question

A compound which can be used in space vehicles both to absorb \[C{O_2}\] and liberate ${O_2}$ is:
(A) $NaOH$
(B) $N{a_2}O$
(C) $N{a_2}{O_2}$
(D) $CaO + NaOH$

Answer 1

Hint: As we know that alkali metals burn in air to form different kinds of oxides which can be used in space vehicles. These oxides react with carbon dioxide present in the air and help in releasing oxygen for breathing purposes.

Complete step by step solution: As we know that alkali metals burns in air to form different kind of oxides so when the sodium metal is heated with excess amount of air it results in the formation of peroxide $N{a_2}{O_2}$ and some superoxide $Na{O_2}$ which we can show by the following equation:
$4Na + {O_2} \to N{a_2}{O_2}$ (sodium peroxide).
Let us now talk about the role of sodium peroxide.
Sodium peroxide is widely used as an oxidising agent in inorganic chemistry and it is also used as a source of oxygen in space vehicles like spacecraft. Sodium peroxide reacts with carbon dioxide present in the air supply in spacecraft resulting in formation of sodium carbonate and liberating oxygen gas which is used for breathing purposes in space. The reaction can be shown in the following equation:
$2N{a_2}{O_2} + C{O_2} \to 2N{a_2}C{O_3} + {O_2}$
Sodium hydroxide also reacts with carbon dioxide but it does not liberate oxygen instead it results in the formation of water molecules. Thus it is not used in space vehicles.
Sodium oxide reacts with carbon dioxide to produce sodium carbonate only which is an acid base neutralization reaction, hence it is also not used in space vehicles.
Sodium hydroxide and calcium gives calcium hydroxide and sodium oxide thus they are also not used in space vehicles.

Hence, the correct answer is (C).

Note: Sodium peroxide is colourless when pure and yellowish solid when sodium is heated in excess oxygen. It is also used in scuba gear as well as submarines for breathing purposes. It decomposes to sodium oxide and results in release of oxygen at approximately $930K$.