The bezylic carbon in `C_6H_5-CH_2-CH_2-COOH` is

Options

A. linearly placed with respect to benzene ring and carbonyl group
B. trigonaly shaped
C. tetrahedral in shape
D. at `90^@` to the plane of benzene bing

Answer

To determine the benzylic carbon in the compound \( C_6H_5-CH_2-CH_2-COOH \), we will follow these steps:

### Step 1: Understand the Structure
The compound \( C_6H_5-CH_2-CH_2-COOH \) consists of a benzene ring (denoted by \( C_6H_5 \)) attached to a carbon chain that includes a carboxylic acid group (\( -COOH \)).

### Step 2: Draw the Structure
To visualize the compound, we can draw it as follows:
- Start with a benzene ring.
- Attach a \( CH_2 \) group to one of the carbons in the benzene ring.
- Attach another \( CH_2 \) group to the first \( CH_2 \).
- Finally, attach the \( -COOH \) group to the second \( CH_2 \).

The structure looks like this:
```
C6H5
|
CH2
|
CH2
|
COOH
```

### Step 3: Identify the Benzylic Carbon
The benzylic carbon is defined as the carbon atom that is directly attached to the benzene ring. In our structure, the first \( CH_2 \) group (the one connected to the benzene) is the benzylic carbon.

### Step 4: Analyze the Benzylic Carbon
The benzylic carbon is:
- Attached to the benzene ring by a sigma bond.
- Has two hydrogen atoms attached to it and is connected to another carbon (the second \( CH_2 \)).

### Step 5: Determine Hybridization
The benzylic carbon forms four sigma bonds:
1. One with the benzene ring.
2. Two with hydrogen atoms.
3. One with the adjacent \( CH_2 \) group.

The steric number of this carbon is 4 (4 sigma bonds and no lone pairs), indicating that it is \( sp^3 \) hybridized.

### Step 6: Conclusion
Since the benzylic carbon is the one directly attached to the benzene ring, we conclude that the benzylic carbon in \( C_6H_5-CH_2-CH_2-COOH \) is the first \( CH_2 \) carbon.