Acetone reacts with phosphorous pentachloride to give:

Options

A. Vic-dihalide
B. `alpha, alpha` -dihalide
C. Gem-dihalide
D. `alpha, omega`- dihalide

Answer

To solve the question of what product is formed when acetone reacts with phosphorus pentachloride (PCl5), we can follow these steps:

### Step 1: Identify the structure of acetone
Acetone is a simple ketone with the molecular formula \( \text{C}_3\text{H}_6\text{O} \). Its structure can be represented as:
\[ \text{CH}_3\text{C}(\text{O})\text{CH}_3 \]
This means it has a carbonyl group (C=O) flanked by two methyl groups (CH3).

**Hint:** Remember that acetone is a ketone, which means it has a carbonyl group (C=O) between two carbon atoms.

### Step 2: Understand the reaction with PCl5
Phosphorus pentachloride (PCl5) is a reagent that can convert alcohols and carbonyl compounds into chlorinated products. In the case of acetone, the carbonyl group will react with PCl5.

**Hint:** PCl5 can replace the oxygen in the carbonyl group with chlorine atoms through a nucleophilic substitution reaction.

### Step 3: Predict the reaction mechanism
When acetone reacts with PCl5, the carbonyl oxygen is replaced by chlorine atoms. Since acetone has one carbonyl group, it will lead to the formation of a geminal dihalide. The reaction can be visualized as follows:
1. The carbonyl oxygen (C=O) is replaced by two chlorine atoms (Cl).
2. This results in the formation of a compound where both chlorine atoms are attached to the same carbon atom.

**Hint:** A geminal dihalide is formed when two halogen atoms are bonded to the same carbon atom.

### Step 4: Write the product
The product of this reaction will be:
\[ \text{Me}_2\text{C}(\text{Cl})_2 \]
This indicates that we have a carbon atom with two chlorine atoms and two methyl groups attached to it, which is a geminal dihalide.

**Hint:** The final product is a geminal dihalide because both chlorine atoms are attached to the same carbon atom.

### Conclusion
The reaction of acetone with phosphorus pentachloride yields a geminal dihalide, specifically:
\[ \text{Me}_2\text{C}(\text{Cl})_2 \]

### Final Answer
The product formed when acetone reacts with phosphorus pentachloride is a geminal dihalide.

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