Hydrogen bonding is maximum in

Options

A. `C_6H_5OH`
B. `C_6H_5COOH`
C. `CH_3CH_2OH`
D. `CH_3COCH_3`.

Answer

To determine which compound exhibits the maximum hydrogen bonding, we will analyze the given options based on the presence of hydrogen atoms bonded to highly electronegative atoms (like O, N, or F) and the ability to form hydrogen bonds.

### Step-by-Step Solution:

1. **Understanding Hydrogen Bonding**:
Hydrogen bonding occurs when a hydrogen atom is covalently bonded to a highly electronegative atom (such as oxygen, nitrogen, or fluorine) and is attracted to another electronegative atom with a lone pair of electrons.

2. **Identifying the Compounds**:
The compounds provided are:
- Option 1: C6H5OH (Phenol)
- Option 2: C6H5COOH (Benzoic Acid)
- Option 3: Acetone (CH3C(=O)CH3)

3. **Analyzing Each Compound**:
- **C6H5OH (Phenol)**:
- Contains one hydroxyl (-OH) group.
- Can form one hydrogen bond with another molecule of phenol.

- **C6H5COOH (Benzoic Acid)**:
- Contains a carboxylic acid group (-COOH).
- Can form two hydrogen bonds: one from the -OH group to another electronegative atom and one from the carbonyl oxygen (C=O) to a hydrogen atom of another molecule.

- **Acetone (CH3C(=O)CH3)**:
- Contains a carbonyl group (C=O) but does not have any hydrogen atoms bonded to an electronegative atom (like O or N) that can participate in hydrogen bonding.
- Therefore, it cannot form hydrogen bonds.

4. **Comparing Hydrogen Bonding Capacity**:
- **Phenol**: 1 hydrogen bond.
- **Benzoic Acid**: 2 hydrogen bonds.
- **Acetone**: 0 hydrogen bonds.

5. **Conclusion**:
Based on the analysis, **C6H5COOH (Benzoic Acid)** exhibits the maximum hydrogen bonding capacity among the given options.

### Final Answer:
Hydrogen bonding is maximum in C6H5COOH (Benzoic Acid).