Which of the following form dimeric halides

Options

A. Al
B. Mg
C. In
D. Ga

Explanation

To determine which of the given compounds form dimeric halides, we need to analyze the halides of the elements mentioned.

### Step-by-Step Solution:

1. **Identify the Compounds**: The question asks about dimeric halides, which typically refers to compounds that exist as dimers in their molecular form. The compounds mentioned in the video transcript are Aluminum chloride (AlCl3), Magnesium chloride (MgCl2), Indium chloride (InCl3), and Gallium chloride (GaCl3).

2. **Analyze Aluminum Chloride (AlCl3)**:
- Aluminum chloride is known to exist as a dimer (Al2Cl6) in the solid state. This dimerization occurs due to the covalent nature of AlCl3 and its tendency to form a stable structure through dimerization.
- **Conclusion**: AlCl3 forms a dimeric halide.

3. **Analyze Magnesium Chloride (MgCl2)**:
- Magnesium chloride is an ionic compound and does not form dimers. It exists as Mg2+ and Cl- ions in a stable ionic lattice.
- **Conclusion**: MgCl2 does not form a dimeric halide.

4. **Analyze Indium Chloride (InCl3)**:
- Indium chloride can also exist as a dimer (In2Cl6) in the solid state, similar to aluminum chloride. This is due to the covalent character of the compound.
- **Conclusion**: InCl3 forms a dimeric halide.

5. **Analyze Gallium Chloride (GaCl3)**:
- Gallium chloride, like AlCl3 and InCl3, can exist as a dimer (Ga2Cl6) in the solid state. The dimerization is a result of its covalent bonding characteristics.
- **Conclusion**: GaCl3 forms a dimeric halide.

### Final Answer:
The compounds that form dimeric halides are:
1. Aluminum chloride (AlCl3)
2. Indium chloride (InCl3)
3. Gallium chloride (GaCl3)

Thus, the answer is **1, 3, and 4** (AlCl3, InCl3, and GaCl3).

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