Glycerol reacts with `P_(4)+I_(2)` to form:

Options

A. Aldehyde
B. Allyl iodide
C. Allyl alcohol
D. Acetylene

Answer

To solve the question of what compound is formed when glycerol reacts with \( P_4 + I_2 \), we can follow these steps:

### Step 1: Understand the structure of glycerol
Glycerol, also known as glycerin, has the chemical formula \( C_3H_8O_3 \). Its structure consists of three hydroxyl (–OH) groups, which can be represented as:
\[ \text{Glycerol: } CH_2OH - CH(OH) - CH_2OH \]

### Step 2: Identify the reaction with \( P_4 + I_2 \)
When glycerol reacts with phosphorus (P) and iodine (I), the hydroxyl groups (–OH) in glycerol are replaced by iodine (I) atoms. This reaction can be summarized as follows:
\[ \text{Glycerol} + P_4 + I_2 \rightarrow \text{Iodinated glycerol} \]
The reaction replaces each –OH group with an iodine atom, resulting in:
\[ CH_2I - CHI - CH_2I \]

### Step 3: Recognize the instability of the iodinated compound
The iodinated compound formed (which has three iodine substituents) is unstable. The presence of multiple iodine atoms leads to the breaking of bonds, resulting in the formation of a double bond.

### Step 4: Formation of the alkene
As the unstable iodinated compound breaks down, it can lead to the formation of an alkene. The resulting compound from this process is:
\[ CH_2 = CH - CH_2I \]
This compound is known as allyl iodide.

### Step 5: Conclusion
Thus, when glycerol reacts with \( P_4 + I_2 \), the final product formed is allyl iodide.

### Final Answer:
The compound formed when glycerol reacts with \( P_4 + I_2 \) is **allyl iodide**.

---