The nitrate of which metal left globule on heating strongly

Options

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

Explanation

To determine which metal nitrate leaves a globule upon strong heating, we can analyze the given options: \( \text{Pb(NO}_3\text{)}_2 \) (Lead nitrate), \( \text{NaNO}_3 \) (Sodium nitrate), \( \text{Hg(NO}_3\text{)}_2 \) (Mercury nitrate), and \( \text{Cu(NO}_3\text{)}_2 \) (Copper nitrate).

### Step-by-Step Solution:

1. **Identify the Nitrates**: We have four metal nitrates to consider:
- \( \text{AgNO}_3 \) (Silver nitrate)
- \( \text{Pb(NO}_3\text{)}_2 \) (Lead nitrate)
- \( \text{NaNO}_3 \) (Sodium nitrate)
- \( \text{Cu(NO}_3\text{)}_2 \) (Copper nitrate)

2. **Understand the Decomposition of Nitrates**: When metal nitrates are heated, they generally decompose to form metal oxides, nitrogen dioxide, and oxygen. However, some nitrates decompose differently.

3. **Analyze Each Nitrate**:
- **Silver Nitrate (\( \text{AgNO}_3 \))**: When heated, it decomposes as follows:
\[ 2 \text{AgNO}_3 \rightarrow 2 \text{Ag} + 2 \text{NO}_2 + \text{O}_2 \]
This reaction produces metallic silver, which can form a globule.

- **Lead Nitrate (\( \text{Pb(NO}_3\text{)}_2 \))**: Decomposes to lead oxide, nitrogen dioxide, and oxygen:
\[ 2 \text{Pb(NO}_3\text{)}_2 \rightarrow 2 \text{PbO} + 4 \text{NO}_2 + \text{O}_2 \]
This does not produce a globule of metal.

- **Sodium Nitrate (\( \text{NaNO}_3 \))**: Decomposes to sodium nitrite and oxygen:
\[ 2 \text{NaNO}_3 \rightarrow 2 \text{NaNO}_2 + \text{O}_2 \]
This does not produce a globule of metal.

- **Copper Nitrate (\( \text{Cu(NO}_3\text{)}_2 \))**: Decomposes to copper oxide, nitrogen dioxide, and oxygen:
\[ 2 \text{Cu(NO}_3\text{)}_2 \rightarrow 2 \text{CuO} + 4 \text{NO}_2 + \text{O}_2 \]
This does not produce a globule of metal.

4. **Conclusion**: The only nitrate that leaves a globule of metal upon strong heating is silver nitrate (\( \text{AgNO}_3 \)).

### Final Answer:
The nitrate of silver metal (\( \text{AgNO}_3 \)) leaves a globule on heating strongly.

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