Question

The oxide that gives H\(_2\)O\(_2\) most readily on treatment with H\(_2\)O is :

• A. PbO\(_2\)
• B. BaO\(_2\).8H\(_2\)O
• C. Na\(_2\)O\(_2\)
• D. SnO\(_2\)

Hint:

To produce H\(_2\)O\(_2\), you need a peroxide, which contains the \( \text{O}_2^{2-} \) ion. Oxides like PbO\(_2\) have the metal in a higher oxidation state (+4) and contain the \( \text{O}^{2-} \) ion. Alkali metal peroxides (like Na\(_2\)O\(_2\)) are generally more reactive with water than alkaline earth metal peroxides (like BaO\(_2\)).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need to identify which of the given oxides reacts most readily with water to produce hydrogen peroxide (H\(_2\)O\(_2\)).
Step 2: Detailed Explanation:
Let's analyze the nature of each oxide and its reaction with water.
- PbO\(_2\) and SnO\(_2\): These are dioxides where the metals (Pb and Sn) are in the +4 oxidation state. They are not peroxides. They are largely inert to water and do not produce H\(_2\)O\(_2\).
- BaO\(_2\): This is barium peroxide. It contains the peroxide ion (O\(_2\)\(^{2-}\)). While it can produce H\(_2\)O\(_2\), the reaction is typically carried out with an acid (like dilute H\(_2\)SO\(_4\)), not just water. The reaction with water is very slow.
\[ \text{BaO}_2(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{BaSO}_4(s) + \text{H}_2\text{O}_2(aq) \] - Na\(_2\)O\(_2\): This is sodium peroxide, an alkali metal peroxide. It reacts readily and exothermically with water to produce sodium hydroxide and hydrogen peroxide. To prevent the decomposition of H\(_2\)O\(_2\) by the heat generated, the reaction is typically carried out with cold water or ice.
\[ \text{Na}_2\text{O}_2(s) + 2\text{H}_2\text{O}(l) \rightarrow 2\text{NaOH}(aq) + \text{H}_2\text{O}_2(aq) \] Comparing the options, Na\(_2\)O\(_2\) is the oxide that gives H\(_2\)O\(_2\) most readily upon direct treatment with water.
Step 3: Final Answer:
Sodium peroxide (Na\(_2\)O\(_2\)) gives H\(_2\)O\(_2\) most readily on treatment with H\(_2\)O.