An inorganic compound first metls then resolidifies and then liberates a gas. It may be

Options

A. `MnO_(2)`
B. `Al_(2)O_(3)`
C. `KMnO_(4)`
D. `KClO_(3)`

Explanation

To solve the question regarding the inorganic compound that first melts, then resolidifies, and then liberates a gas, we can analyze the behavior of potassium chlorate (KClO3) when it is heated.

### Step-by-Step Solution:

1. **Understanding the Behavior of KClO3**:
- Potassium chlorate (KClO3) is known to undergo thermal decomposition when heated. This means that it breaks down into simpler substances upon heating.

2. **Heating KClO3**:
- When KClO3 is heated, it first melts. The melting point of KClO3 is around 360 °C. As it reaches this temperature, it transitions from solid to liquid.

3. **Decomposition Reaction**:
- Upon further heating, KClO3 decomposes into potassium chloride (KCl) and oxygen gas (O2). The balanced chemical equation for this reaction is:
\[ 2 \text{KClO}_3 (s) \rightarrow 2 \text{KCl} (s) + 3 \text{O}_2 (g) \]

4. **Resolidification**:
- After the initial melting, as the temperature continues to rise and KClO3 decomposes, the remaining solid product (KCl) can resolidify. This happens because the temperature may drop after the reaction or because the KCl has a higher melting point than KClO3.

5. **Gas Liberation**:
- During the decomposition of KClO3, oxygen gas (O2) is liberated. This is a key point in confirming that KClO3 fits the description given in the question.

6. **Conclusion**:
- Therefore, the inorganic compound that first melts, then resolidifies, and liberates a gas is potassium chlorate (KClO3).

### Final Answer:
The inorganic compound is **KClO3**.