`Al Cl_3` is

Options

A. Anhydrous and covalent
B. Anhydrous and ionic
C. Covalent and basic
D. Coordinate and acidic

Answer

To determine the nature of \( \text{AlCl}_3 \), we will analyze its properties step by step.

### Step 1: Identify the nature of \( \text{AlCl}_3 \)
- **Anhydrous Nature**: \( \text{AlCl}_3 \) is referred to as anhydrous because it does not contain water molecules in its structure. This is significant in understanding its behavior in different states.

### Step 2: Analyze the bonding type
- **Covalent Nature**: \( \text{AlCl}_3 \) is primarily covalent in nature. This is because aluminum (Al) and chlorine (Cl) share electrons to form covalent bonds. The covalent character is more pronounced due to the small size and high charge density of the aluminum ion.

### Step 3: Consider its behavior in different states
- **Ionic Behavior in Aqueous Medium**: When \( \text{AlCl}_3 \) is dissolved in water, it dissociates into ions. This means that in an aqueous solution, it behaves as an ionic compound:
\[ \text{AlCl}_3 \rightarrow \text{Al}^{3+} + 3\text{Cl}^- \]

### Step 4: Examine its vapor phase
- **Dimer Formation in Vapor Phase**: In the vapor phase, \( \text{AlCl}_3 \) exists as a dimer, which can be represented as:
\[ 2\text{AlCl}_3 \rightarrow \text{Al}_2\text{Cl}_6 \]
This dimerization occurs due to the covalent nature of the compound, leading to the formation of a stable dimer.

### Conclusion
Based on the analysis, we conclude that \( \text{AlCl}_3 \) is:
- Anhydrous
- Covalent in nature
- Ionic in aqueous solution
- Dimeric in vapor phase

### Final Answer
Thus, the correct characterization of \( \text{AlCl}_3 \) is that it is **anhydrous and covalent**.

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