Which of the following is not formed in iodoform reaction of acetone ?

Options

A. `CH_(3)COCH_(2) I`
B. `ICH_(2)COCH_(2)I`
C. `CH_(3)COCHI_(2)`
D. `CH_(3)COCI_(3)`

Answer

To determine which compound is not formed in the iodoform reaction of acetone, we can follow these steps:

### Step 1: Understand the Iodoform Reaction
The iodoform reaction involves the halogenation of a methyl ketone (like acetone) in the presence of a base (usually NaOH) and iodine (I2). The reaction leads to the formation of iodoform (CHI3) and a carboxylate ion.

### Step 2: Write the Structure of Acetone
Acetone has the chemical formula CH3COCH3. Its structure can be represented as:
```
O
||
CH3 - C - CH3
```

### Step 3: Formation of Enolate Ion
When acetone reacts with NaOH, it abstracts a hydrogen atom from one of the methyl groups, forming an enolate ion:
```
O
||
CH3 - C^- - CH3
```
This enolate ion is reactive and can participate in further reactions.

### Step 4: Halogenation with Iodine
The enolate ion then reacts with iodine (I2). The negative charge on the carbon atom attacks iodine, leading to the formation of a compound where one of the methyl hydrogens is replaced by iodine:
```
O
||
CH3 - C(I) - CH3
```
This compound can further react with NaOH to abstract another hydrogen and form a more substituted product.

### Step 5: Further Halogenation
Repeating the halogenation process results in the formation of a compound with two iodine atoms:
```
O
||
CH3 - C(I2) - CH3
```

### Step 6: Final Product Formation
The final step involves the removal of the leaving group (iodine) to yield iodoform (CHI3) and a carboxylate ion:
```
Iodoform: CHI3
```

### Step 7: Analyze the Options
Now, we need to analyze the given options to determine which compound is not formed during the reaction:
1. **CH3COCH2I** - This compound can be formed during the reaction.
2. **CH3COCI3** - This compound can also be formed during the reaction.
3. **CH3COCHI2** - This compound is formed as a product during the halogenation steps.
4. **CH3COCH3** - This is the starting material (acetone) and is not a product of the reaction.

### Conclusion
The compound that is **not formed** in the iodoform reaction of acetone is **CH3COCH3** (acetone itself).

### Final Answer
The correct answer is **option b**, which is not formed in the iodoform reaction of acetone.

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