Select the correct statement with respect to sodium peroxide ?

Options

A. It decolourises the acidifed `KMnO_4` solution
B. On heating with oxygen at `450^@C` and 300 atm pressure, it becomes paramagnetic
C. It is obtained along with sodium metal, when sodium oxide is heated to a temperature more than `400^@C`
D. It gives both hydrogen peroxide and oxygen gas with water as well as with sulphuric acid.

Explanation

To solve the question regarding sodium peroxide, we will analyze each statement provided in the options one by one.

### Step-by-Step Solution:

1. **Analyze Statement A**:
- **Statement**: "It decolorizes the acidified KMnO4 solution."
- **Explanation**: Sodium peroxide (Na2O2) reacts with the permanganate ion (MnO4^-) in an acidic medium. The reaction leads to the reduction of MnO4^- to Mn^2+, which is colorless, thus decolorizing the pink solution of KMnO4.
- **Conclusion**: Statement A is **correct**.

2. **Analyze Statement B**:
- **Statement**: "On heating with oxygen at 450 degrees Celsius and 300 atm pressure, it becomes paramagnetic."
- **Explanation**: When sodium peroxide is heated in the presence of oxygen, it can form sodium superoxide (NaO2). The superoxide ion (O2^-) has one unpaired electron, which makes it paramagnetic.
- **Conclusion**: Statement B is **correct**.

3. **Analyze Statement C**:
- **Statement**: "It is obtained along with sodium metal when sodium oxide is heated to a temperature more than 400 degrees Celsius."
- **Explanation**: When sodium metal is heated in oxygen at high temperatures (above 400°C), sodium oxide (Na2O) can react to form sodium peroxide (Na2O2) as well.
- **Conclusion**: Statement C is **correct**.

4. **Analyze Statement D**:
- **Statement**: "It gives both hydrogen peroxide and oxygen gas with water as well as with sulfuric acid."
- **Explanation**: When sodium peroxide reacts with water, it produces hydrogen peroxide (H2O2) and oxygen gas (O2). Similarly, when it reacts with sulfuric acid, it also produces hydrogen peroxide and oxygen gas.
- **Conclusion**: Statement D is **correct**.

### Final Conclusion:
All statements A, B, C, and D regarding sodium peroxide are correct.