The reaction of ethylene glycol with `PI_(3)` gives :

Options

A. `ICH_(2) CH_(2)I`
B. `CH_(2) = CH_(2)`
C. `CH_(2) = CHI`
D. ICH=CHI

Answer

To solve the problem of what product is formed when ethylene glycol reacts with phosphorus triiodide (PI3), we can follow these steps:

### Step 1: Understand the Structure of Ethylene Glycol
Ethylene glycol has the chemical formula C2H6O2 and can be represented as:
\[ \text{HO-CH}_2-\text{CH}_2-\text{OH} \]
This means it has two hydroxyl (–OH) groups.

### Step 2: Reaction with PI3
When ethylene glycol reacts with phosphorus triiodide (PI3), the hydroxyl groups (–OH) are replaced by iodine (I) atoms. The reaction can be summarized as follows:
\[ \text{HO-CH}_2-\text{CH}_2-\text{OH} + 2 \text{PI}_3 \rightarrow \text{I-CH}_2-\text{CH}_2-\text{I} + 2 \text{H}_3\text{PO}_3 \]
This indicates that each –OH group is replaced by an iodine atom, resulting in the formation of ethylene diiodide.

### Step 3: Identify the Product
The product formed from this reaction is:
\[ \text{I-CH}_2-\text{CH}_2-\text{I} \]
This compound is known as ethylene diiodide.

### Step 4: Consider Possible Further Reactions
In the presence of steric hindrance due to the bulky iodine atoms, further reactions can occur. The steric hindrance can lead to the elimination of iodine (I2) and the formation of a double bond between the carbon atoms:
\[ \text{I-CH}_2-\text{CH}_2-\text{I} \rightarrow \text{CH}_2=\text{CH}_2 + \text{I}_2 \]
This results in the formation of ethene.

### Final Answer
The primary product of the reaction of ethylene glycol with PI3 is ethylene diiodide (I-CH2-CH2-I). However, due to steric hindrance, ethene (CH2=CH2) can also be formed as a secondary product.

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