Which compound will liberate oxygen when reacts with ice cold water ?

Options

A. `Na_2O_2`
B. `KO_2`
C. `Na_2O`
D. `Cs_2O_2`

Answer

To solve the question of which compound will liberate oxygen when it reacts with ice-cold water, we will analyze the reactions of the given compounds step by step.

### Step-by-Step Solution:

1. **Identify the Compounds:**
We need to consider the four compounds provided in the options. For this solution, let's assume the compounds are:
- A) Na2O2 (Sodium Peroxide)
- B) KO2 (Potassium Superoxide)
- C) K2O2 (Potassium Peroxide)
- D) Na2O (Sodium Oxide)

2. **Reaction of Na2O2 with Water:**
- When sodium peroxide (Na2O2) reacts with water, the reaction can be written as:
\[ \text{Na}_2\text{O}_2 + 2\text{H}_2\text{O} \rightarrow 2\text{NaOH} + \text{H}_2\text{O}_2 \]
- This reaction produces hydrogen peroxide (H2O2) but does not liberate oxygen gas (O2).

3. **Reaction of KO2 with Water:**
- When potassium superoxide (KO2) reacts with water, the reaction is:
\[ 4\text{KO}_2 + 2\text{H}_2\text{O} \rightarrow 4\text{KOH} + 3\text{O}_2 + 2\text{H}_2\text{O}_2 \]
- This reaction produces potassium hydroxide (KOH), hydrogen peroxide (H2O2), and liberates oxygen gas (O2).

4. **Reaction of K2O2 with Water:**
- When potassium peroxide (K2O2) reacts with water, the reaction can be represented as:
\[ \text{K}_2\text{O}_2 + 2\text{H}_2\text{O} \rightarrow 2\text{KOH} + \text{H}_2\text{O}_2 \]
- Similar to Na2O2, this reaction produces hydrogen peroxide but does not liberate oxygen gas.

5. **Reaction of Na2O with Water:**
- When sodium oxide (Na2O) reacts with water, the reaction is:
\[ \text{Na}_2\text{O} + \text{H}_2\text{O} \rightarrow 2\text{NaOH} \]
- This reaction only produces sodium hydroxide (NaOH) and does not liberate oxygen gas.

6. **Conclusion:**
- Among the compounds analyzed, only KO2 (Potassium Superoxide) liberates oxygen gas when it reacts with ice-cold water. Therefore, the correct answer is:
**B) KO2 (Potassium Superoxide)**