Which one of the following nitrates will leaves behind a metal on strong heating?

Options

A. Copper nitrate
B. Manganese nitrate
C. Silver nitrate
D. Ferric nitrate

Explanation

To determine which nitrate will leave behind a metal upon strong heating, we will analyze the thermal decomposition reactions of each of the given nitrates: copper nitrate, manganese nitrate, silver nitrate, and ferric nitrate.

### Step-by-Step Solution:

1. **Copper Nitrate (Cu(NO3)2)**:
- When copper nitrate is strongly heated, it decomposes as follows:
\[ 2 \text{Cu(NO}_3\text{)}_2 \rightarrow 2 \text{CuO} + 4 \text{NO}_2 + \text{O}_2 \]
- The products are copper oxide (CuO), nitrogen dioxide (NO2), and oxygen (O2). No elemental copper metal is produced.

2. **Manganese Nitrate (Mn(NO3)2)**:
- The thermal decomposition of manganese nitrate is represented by:
\[ 2 \text{Mn(NO}_3\text{)}_2 \rightarrow 2 \text{MnO} + 4 \text{NO}_2 + \text{O}_2 \]
- Here, manganese oxide (MnO) is formed along with nitrogen dioxide and oxygen. Again, no elemental manganese metal is produced.

3. **Silver Nitrate (AgNO3)**:
- The reaction for silver nitrate upon strong heating is:
\[ 2 \text{AgNO}_3 \rightarrow 2 \text{Ag} + 2 \text{NO}_2 + \text{O}_2 \]
- This decomposition yields silver metal (Ag), nitrogen dioxide, and oxygen. This indicates that silver nitrate does leave behind a metal upon heating.

4. **Ferric Nitrate (Fe(NO3)3)**:
- The decomposition of ferric nitrate can be represented as:
\[ 2 \text{Fe(NO}_3\text{)}_3 \rightarrow \text{Fe}_2\text{O}_3 + 6 \text{NO}_2 + 3 \text{O}_2 \]
- The products include ferric oxide (Fe2O3), nitrogen dioxide, and oxygen. No elemental iron is produced.

### Conclusion:
Among the nitrates analyzed, **silver nitrate (AgNO3)** is the only compound that leaves behind a metal (silver) upon strong heating.

### Final Answer:
**Silver Nitrate (AgNO3)**

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