The metal oxide which decomposes on heating is/are:

Options

A. ZnO
B. `Al_(2)O_(3)`
C. `Ag_(2)O`
D. `HgO`

Answer

To determine which metal oxides decompose upon heating, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the Metal Oxides**: The options given are:
- A) ZnO (Zinc Oxide)
- B) Al2O3 (Aluminum Oxide)
- C) Ag2O (Silver Oxide)
- D) HgO (Mercury Oxide)

2. **Analyze Zinc Oxide (ZnO)**:
- Zinc oxide is known to be a thermally stable compound.
- **Conclusion**: ZnO does not decompose upon heating.

3. **Analyze Aluminum Oxide (Al2O3)**:
- Aluminum oxide is also a thermally stable compound.
- **Conclusion**: Al2O3 does not decompose upon heating.

4. **Analyze Silver Oxide (Ag2O)**:
- Silver oxide is known to be thermally unstable and decomposes upon heating.
- The decomposition reaction is:
\[ 2 \text{Ag}_2\text{O} \rightarrow 4 \text{Ag} + \text{O}_2 \]
- **Conclusion**: Ag2O decomposes upon heating.

5. **Analyze Mercury Oxide (HgO)**:
- Mercury oxide is also thermally unstable and decomposes upon heating.
- The decomposition reaction is:
\[ 2 \text{HgO} \rightarrow 2 \text{Hg} + \text{O}_2 \]
- **Conclusion**: HgO decomposes upon heating.

6. **Final Conclusion**:
- The metal oxides that decompose upon heating are:
- C) Ag2O (Silver Oxide)
- D) HgO (Mercury Oxide)

### Final Answer:
The metal oxides which decompose on heating are **Ag2O (Silver Oxide)** and **HgO (Mercury Oxide)**.

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