Maximum extent of hydrogen bonding is observed in

Options

A. `C_(6) H_(5)OH`
B. `C_(6)H_(5)COOH`
C. `CH_(3)CH_(2)OH`
D. `CH_(3)COCH_(3)`

Answer

To determine the compound that exhibits the maximum extent of hydrogen bonding, we need to analyze the given compounds based on their ability to form hydrogen bonds.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds mentioned are:
- C6H5OH (Phenol)
- C6H5COH (Benzaldehyde)
- CH3CH2OH (Ethanol)
- CH3C(=O)CH3 (Acetone)

2. **Understanding Hydrogen Bonding**: Hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like oxygen or nitrogen) interacts with another electronegative atom. The strength of hydrogen bonding depends on the electronegativity of the atoms involved and the availability of hydrogen atoms for bonding.

3. **Analyze Each Compound**:
- **C6H5OH (Phenol)**: Contains an -OH group, allowing for hydrogen bonding with other phenol molecules.
- **C6H5COH (Benzaldehyde)**: Contains a carbonyl group (C=O) but lacks an -OH group, limiting its hydrogen bonding capability.
- **CH3CH2OH (Ethanol)**: Contains an -OH group, allowing for hydrogen bonding, but it is a smaller molecule compared to phenol.
- **CH3C(=O)CH3 (Acetone)**: Contains a carbonyl group but does not have an -OH group, so it cannot form hydrogen bonds.

4. **Comparing Hydrogen Bonding Ability**:
- **Phenol (C6H5OH)**: Strong hydrogen bonding due to the presence of the -OH group and its ability to form dimers.
- **Benzaldehyde (C6H5COH)**: Limited hydrogen bonding due to lack of an -OH group.
- **Ethanol (CH3CH2OH)**: Can form hydrogen bonds, but less extensive than phenol.
- **Acetone (CH3C(=O)CH3)**: Cannot form hydrogen bonds.

5. **Conclusion**: Among the compounds analyzed, **C6H5OH (Phenol)** shows the maximum extent of hydrogen bonding due to its ability to form strong hydrogen bonds through its -OH group.

### Final Answer:
The compound that exhibits the maximum extent of hydrogen bonding is **C6H5OH (Phenol)**.