How many HCl molecules are obtained by heating one molecule of hydrated ferric chloride ?

Explanation

To determine how many HCl molecules are obtained by heating one molecule of hydrated ferric chloride (FeCl3·6H2O), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Formula of Hydrated Ferric Chloride**:
The hydrated ferric chloride is represented as FeCl3·6H2O. This indicates that each molecule of FeCl3 is associated with 6 molecules of water.

2. **Write the Balanced Chemical Equation**:
When hydrated ferric chloride is heated, it decomposes. The balanced chemical reaction for the heating of FeCl3·6H2O can be written as:
\[ 2 \text{FeCl}_3 \cdot 6\text{H}_2\text{O} \rightarrow \text{Fe}_2\text{O}_3 + 6 \text{HCl} + 9 \text{H}_2\text{O} \]

3. **Analyze the Reaction**:
From the balanced equation, we see that 2 moles of hydrated ferric chloride yield 6 moles of HCl.

4. **Calculate HCl from One Molecule**:
To find out how many HCl molecules are produced from one molecule of hydrated ferric chloride, we can set up a ratio:
- If 2 moles of FeCl3·6H2O produce 6 moles of HCl, then:
\[ 1 \text{ mole of FeCl}_3 \cdot 6\text{H}_2\text{O} \rightarrow \frac{6}{2} \text{ HCl} = 3 \text{ HCl} \]

5. **Conclusion**:
Therefore, when one molecule of hydrated ferric chloride is heated, it produces 3 molecules of HCl.

### Final Answer:
**3 HCl molecules are obtained by heating one molecule of hydrated ferric chloride.**