Which compound on heating alone does not form `O_(2)` ?

Options

A. `KClO_(4)`
B. `KMnO_(4)`
C. `KNO_(3)`
D. `NH_(4)NO_(2)`

Answer

To solve the question of which compound does not release O2 when heated, we will analyze the thermal decomposition of each of the given compounds.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds we need to analyze are:
- KClO4 (Potassium perchlorate)
- KMnO4 (Potassium permanganate)
- KNO3 (Potassium nitrate)
- NH4NO2 (Ammonium nitrite)

2. **Analyze KClO4**:
- When KClO4 is heated, it decomposes into KCl and O2.
- **Reaction**:
\[ 2 KClO_4 \rightarrow 2 KCl + 3 O_2 \]
- **Conclusion**: KClO4 releases O2 upon heating.

3. **Analyze KMnO4**:
- When KMnO4 is heated, it decomposes into K2MnO4, MnO2, and O2.
- **Reaction**:
\[ 2 KMnO_4 \rightarrow K_2MnO_4 + MnO_2 + O_2 \]
- **Conclusion**: KMnO4 also releases O2 upon heating.

4. **Analyze KNO3**:
- When KNO3 is heated, it decomposes into KNO2 and O2.
- **Reaction**:
\[ 2 KNO_3 \rightarrow 2 KNO_2 + O_2 \]
- **Conclusion**: KNO3 releases O2 upon heating.

5. **Analyze NH4NO2**:
- When NH4NO2 is heated, it decomposes into N2 and H2O.
- **Reaction**:
\[ NH_4NO_2 \rightarrow N_2 + 2 H_2O \]
- **Conclusion**: NH4NO2 does not release O2 upon heating.

6. **Final Conclusion**:
- Among the compounds analyzed, only NH4NO2 does not produce O2 when heated. Therefore, the answer to the question is NH4NO2.

### Answer:
The compound that does not form O2 upon heating is **NH4NO2 (Ammonium nitrite)**.