Question

When water is poured over sodium peroxide, which colourless gas is produced ?

• A. Dihydrogen
• B. Ozone
• C. Dioxygen
• D. Dinitrogen

Hint:

The reaction is: Sodium Peroxide + Water \(\rightarrow\) Sodium Hydroxide + Oxygen. \[ 2\text{Na}_2\text{O}_2 + 2\text{H}_2\text{O} \rightarrow 4\text{NaOH} + \text{O}_2 \] The gas produced is Oxygen (\(\text{O}_2\)), which is also called "Dioxygen". This reaction is sometimes used as a source of oxygen.

Answer 1

The Correct Option is C

Concept: Sodium peroxide (\(\text{Na}_2\text{O}_2\)) is a compound that reacts with water to produce specific products, including a gas. Step 1: The Chemical Reaction Sodium peroxide reacts with water according to the following balanced chemical equation: \[ 2\text{Na}_2\text{O}_2(s) + 2\text{H}_2\text{O}(l) \rightarrow 4\text{NaOH}(aq) + \text{O}_2(g) \] This reaction produces sodium hydroxide (NaOH), which dissolves in the water to form an aqueous solution, and oxygen gas (\(\text{O}_2\)). Step 2: Identifying the Gaseous Product The gaseous product formed in this reaction is oxygen (\(\text{O}_2\)). Oxygen gas is a colourless and odourless gas under standard conditions. Step 3: Analyzing the options % Option (w) (1) Dihydrogen (\(\text{H}_2\)): Hydrogen gas. Not the primary gaseous product from the reaction of sodium peroxide with water. (Highly reactive metals like sodium react with water to produce hydrogen, but sodium peroxide reacts differently). % Option (x) (2) Ozone (\(\text{O}_3\)): An allotrope of oxygen. Not produced in this reaction. % Option (y) (3) Dioxygen (\(\text{O}_2\)): This is the chemical name for molecular oxygen, which is the gas produced. % Option (z) (4) Dinitrogen (\(\text{N}_2\)): Nitrogen gas. Not produced as there is no nitrogen in the reactants. The colourless gas produced is dioxygen (oxygen).