Which of the following is a geminal dihalide ?

Options

A. Ethylene dibromide
B. Propylidene chloride
C. Isopropyl bromide
D. None of the above

Explanation

To determine which of the given compounds is a geminal dihalide, we need to understand the definitions of geminal and vicinal dihalides:

1. **Geminal Dihalide**: A compound where two halogen atoms are attached to the same carbon atom.
2. **Vicinal Dihalide**: A compound where two halogen atoms are attached to adjacent carbon atoms.

Now, let's analyze the options provided:

### Step 1: Analyze Option A - Ethylene Dibromide
- Ethylene dibromide has the structure:
\[ \text{Br}-\text{C}=\text{C}-\text{Br} \]
- In this structure, the bromine atoms are attached to different carbon atoms, making it a vicinal dihalide, not a geminal dihalide.

### Step 2: Analyze Option B - Propylidene Chloride
- Propylidene chloride has the structure:
\[ \text{CH}_3-\text{C}(\text{Cl})=\text{C}(\text{Cl})-\text{H} \]
- Here, both chlorine atoms are attached to the same carbon atom (the carbon in the double bond), making it a geminal dihalide.

### Step 3: Analyze Option C - Isopropyl Bromide
- Isopropyl bromide has the structure:
\[ \text{CH}_3-\text{C}(\text{Br})-\text{CH}_3 \]
- In this case, the bromine atom is attached to one carbon atom, while the other carbon atoms are not bonded to any halogen, which does not qualify as a geminal dihalide.

### Conclusion
After analyzing all the options:
- **Option A** (Ethylene dibromide) is a vicinal dihalide.
- **Option B** (Propylidene chloride) is a geminal dihalide.
- **Option C** (Isopropyl bromide) is neither a geminal nor a vicinal dihalide.

Thus, the correct answer is **Option B: Propylidene Chloride**.