Which of the following substances undergoes chemical change an heating?

Options

A. Sodium chloride
B. Silica
C. Lead nitrate
D. Platinum wire

Answer

To determine which of the given substances undergoes a chemical change upon heating, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Identify the Substances**: The substances given are:
- Sodium Chloride (NaCl)
- Silica (SiO2)
- Lead Nitrate (Pb(NO3)2)
- Platinum Wire (Pt)

2. **Analyze Sodium Chloride**:
- When sodium chloride is heated, it does not decompose or change into a new substance.
- **Conclusion**: No new substance is formed. Therefore, sodium chloride does not undergo a chemical change upon heating.

3. **Analyze Silica**:
- Silica, when heated, remains chemically unchanged and does not produce any new substances.
- **Conclusion**: No new substance is formed. Therefore, silica does not undergo a chemical change upon heating.

4. **Analyze Lead Nitrate**:
- Lead nitrate (Pb(NO3)2) undergoes a decomposition reaction when heated. The reaction can be represented as:
\[ 2 \text{Pb(NO}_3\text{)}_2 \rightarrow 2 \text{PbO} + 4 \text{NO}_2 + \text{O}_2 \]
- In this reaction, lead oxide (PbO), nitrogen dioxide (NO2), and oxygen (O2) are produced, indicating that new substances are formed.
- **Conclusion**: New substances are formed. Therefore, lead nitrate undergoes a chemical change upon heating.

5. **Analyze Platinum Wire**:
- When platinum wire is heated, it does not react or change into a new substance. It remains platinum.
- **Conclusion**: No new substance is formed. Therefore, platinum wire does not undergo a chemical change upon heating.

### Final Conclusion:
The only substance that undergoes a chemical change upon heating is **Lead Nitrate (Pb(NO3)2)**.