Which of the following statement about anhydrous aluminium chloride is correct?

Options

A. It fumes is moist air.
B. It exists as dimer both in the vapour state below `350^(@)C` and in non - polar solvents
C. It is preapared by heating `Al_(2)O_(3)` in a stream of sulphur chloride `(S_(2)Cl_(2))` vapor and chlorine.
D. All of these

Answer

To determine which statement about anhydrous aluminium chloride (AlCl3) is correct, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement:** Anhydrous aluminium chloride fumes in moist air.

**Explanation:** Anhydrous aluminium chloride reacts with moisture in the air to form aluminium hydroxide and hydrochloric acid. The reaction can be represented as:
\[ \text{AlCl}_3 + 3 \text{H}_2\text{O} \rightarrow \text{Al(OH)}_3 + 3 \text{HCl} \]
The hydrochloric acid (HCl) produced is a gas that forms white fumes when it comes into contact with moisture. Therefore, this statement is **correct**.

### Step 2: Analyze the second statement
**Statement:** Anhydrous aluminium chloride exists as a dimer in both vapor state below 350 degrees Celsius and in non-polar solvents.

**Explanation:** In the vapor state and in non-polar solvents, anhydrous aluminium chloride exists as a dimer, represented as Al2Cl6. The dimerization occurs as follows:
\[ 2 \text{AlCl}_3 \rightarrow \text{Al}_2\text{Cl}_6 \]
This dimerization is favored in non-polar solvents like benzene. Thus, this statement is also **correct**.

### Step 3: Analyze the third statement
**Statement:** Anhydrous aluminium chloride is prepared by heating Al2O3 in a stream of sulfur chloride vapor and chlorine.

**Explanation:** The preparation of anhydrous aluminium chloride can be done by reacting aluminium oxide (Al2O3) with sulfur chloride (SCl2) and chlorine gas (Cl2). The reaction can be summarized as:
\[ \text{Al}_2\text{O}_3 + 3 \text{SCl}_2 + 6 \text{Cl}_2 \rightarrow 2 \text{AlCl}_3 + 3 \text{SO}_2 + 3 \text{Cl}_2 \]
This confirms that the statement is **correct**.

### Conclusion
Since all three statements about anhydrous aluminium chloride are correct, the final answer is:
**D: All of these.**

---