Nitrogen dioxide is not produced on heating

Options

A. `KNO_(3)`
B. `Pb(NO_(3))_(2)`
C. `Cu(NO_(3))_(2)`
D. `AgNO_(3)`

Explanation

To solve the question "Nitrogen dioxide is not produced on heating," we need to analyze the options provided and determine which reaction does not yield nitrogen dioxide (NO2) upon heating.

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to consider the compounds mentioned in the question and their behavior when heated. The compounds mentioned are potassium nitrate (KNO3), lead nitrate (Pb(NO3)2), copper nitrate (Cu(NO3)2), and silver nitrate (AgNO3).

2. **Analyze Potassium Nitrate (KNO3)**:
- When KNO3 is heated, it decomposes to form potassium nitrite (KNO2) and oxygen (O2):
\[ 2 KNO_3 \rightarrow 2 KNO_2 + O_2 \]
- **Conclusion**: NO2 is not produced in this reaction.

3. **Analyze Lead Nitrate (Pb(NO3)2)**:
- When lead nitrate is heated, it decomposes to form lead oxide (PbO), nitrogen dioxide (NO2), and oxygen (O2):
\[ 2 Pb(NO_3)_2 \rightarrow 2 PbO + 4 NO_2 + O_2 \]
- **Conclusion**: NO2 is produced in this reaction.

4. **Analyze Copper Nitrate (Cu(NO3)2)**:
- When copper nitrate is heated, it decomposes to form copper oxide (CuO) and nitrogen dioxide (NO2):
\[ 2 Cu(NO_3)_2 \rightarrow 2 CuO + 4 NO_2 + O_2 \]
- **Conclusion**: NO2 is produced in this reaction.

5. **Analyze Silver Nitrate (AgNO3)**:
- When silver nitrate is heated, it decomposes to form silver oxide (Ag2O) and nitrogen dioxide (NO2):
\[ 2 AgNO_3 \rightarrow Ag_2O + 2 NO_2 + O_2 \]
- **Conclusion**: NO2 is produced in this reaction.

6. **Final Conclusion**: Among the options analyzed, only potassium nitrate (KNO3) does not produce nitrogen dioxide when heated. Therefore, the answer to the question is that nitrogen dioxide is not produced when heating potassium nitrate.

### Answer:
**Potassium nitrate (KNO3) is the compound that does not produce nitrogen dioxide upon heating.**