`Pcl_(5)` reacts with a compound containing

Options

A. `-SO_(3)` group
B. `-OH` group
C. `NO_(3)` group
D. `-NO` group

Explanation

To solve the question regarding the reaction of \( PCl_5 \) with a compound containing a specific functional group, we can follow these steps:

### Step 1: Identify the nature of \( PCl_5 \)
\( PCl_5 \) (phosphorus pentachloride) is known to behave as a Lewis acid. This means it can accept electron pairs due to the presence of vacant d-orbitals.

**Hint:** Recall that Lewis acids are electron pair acceptors.

### Step 2: Determine the functional groups that can react with \( PCl_5 \)
Common functional groups that can react with \( PCl_5 \) include hydroxyl groups (–OH) and sulfonic acid groups (–SO₃H). These groups can donate electron pairs to \( PCl_5 \).

**Hint:** Think about functional groups that have lone pairs of electrons available for donation.

### Step 3: Analyze the reaction mechanism
When \( PCl_5 \) reacts with a compound containing an –OH group, the following mechanism occurs:
1. The lone pair of electrons on the oxygen atom of the –OH group attacks the phosphorus atom in \( PCl_5 \).
2. This leads to the formation of an intermediate complex.
3. The complex then eliminates a chloride ion (Cl⁻), resulting in the formation of an alkyl chloride (RCl).
4. The by-products of this reaction are \( POCl_3 \) and \( HCl \).

**Hint:** Consider the steps of nucleophilic attack and subsequent elimination in the reaction.

### Step 4: Identify the correct compound
Since \( PCl_5 \) specifically reacts with compounds that contain hydroxyl groups (–OH), the correct answer to the question is that \( PCl_5 \) will react with compounds containing the –OH group.

**Hint:** Focus on the functional groups that are compatible with Lewis acid behavior.

### Final Answer
Thus, \( PCl_5 \) reacts with compounds containing the –OH group.

**Correct Option:** Compounds containing the –OH group (option 2 is the correct answer).