Which of the following reaction(s) is /are used for the preparation of anhydrous `FeCl_(3)`?

Options

A. `FeCl_(3).6H_(2)O+6SOCl_(2)toFeCl_(3)+12HCl+6SO_(2)`
B. `Fe(OH)_(3)downarrow+3HCl to FeCl_(3)+3H_(2)O`
C. `2Fe+4HCl(aq)+Cl_(2)to2FeCl_(3)+2H_(2)`
D. `2Fe+3Cl_(2)(dry) to 2FeCl_(3)`

Answer

To determine which reactions can be used to prepare anhydrous FeCl₃, we will analyze the provided methods step by step.

### Step 1: Understand the Requirement
We need to prepare anhydrous ferric chloride (FeCl₃). Anhydrous means that the compound does not contain any water molecules.

### Step 2: Analyze the First Method
The first method involves the reaction of hydrated ferric chloride (FeCl₃·6H₂O) with thionyl chloride (SOCl₂):
\[ \text{FeCl}_3 \cdot 6\text{H}_2\text{O} + \text{SOCl}_2 \rightarrow \text{FeCl}_3 + 6\text{HCl} + \text{SO}_2 \]

- **Outcome**: This reaction removes the water of crystallization and yields anhydrous FeCl₃.
- **Conclusion**: This method is suitable for preparing anhydrous FeCl₃.

### Step 3: Analyze the Second Method
The second method involves the reaction of iron with aqueous hydrochloric acid (HCl):
\[ \text{Fe} + 6\text{HCl (aq)} \rightarrow \text{FeCl}_3 \cdot 6\text{H}_2\text{O} \]

- **Outcome**: This reaction produces hydrated FeCl₃, which is not anhydrous.
- **Conclusion**: This method is not suitable for preparing anhydrous FeCl₃.

### Step 4: Analyze the Third Method
The third method involves the reaction of iron with aqueous hydrochloric acid and chlorine gas:
\[ \text{Fe} + 4\text{HCl (aq)} + \text{Cl}_2 \rightarrow \text{FeCl}_3 \cdot 6\text{H}_2\text{O} \]

- **Outcome**: Similar to the second method, this also produces hydrated FeCl₃.
- **Conclusion**: This method is not suitable for preparing anhydrous FeCl₃.

### Step 5: Analyze the Fourth Method
The fourth method involves directly heating iron and passing chlorine gas over it:
\[ \text{Fe} + \text{Cl}_2 \rightarrow \text{FeCl}_3 \]

- **Outcome**: This reaction produces anhydrous FeCl₃ directly.
- **Conclusion**: This method is suitable for preparing anhydrous FeCl₃.

### Final Conclusion
The methods that can be used for the preparation of anhydrous FeCl₃ are:
1. The reaction of FeCl₃·6H₂O with SOCl₂.
2. The direct reaction of iron with chlorine gas.

### Summary of Suitable Methods
- **Suitable Methods**:
- Reaction of FeCl₃·6H₂O with SOCl₂.
- Direct reaction of iron with chlorine gas.