Which of the following species shows intramolecular hydrogen bonding ?

Options

A. H_(2)O
B. `HF`
C.
D. `C Cl_(3)CH(OH)_(2)`

Explanation

To determine which of the given species shows intramolecular hydrogen bonding, we need to analyze each option based on the definition and characteristics of intramolecular hydrogen bonding.

### Step-by-Step Solution:

1. **Understanding Intramolecular Hydrogen Bonding**:
- Intramolecular hydrogen bonding occurs when a hydrogen atom bonded to an electronegative atom (like O, N, or F) forms a bond with another electronegative atom within the same molecule, creating a loop or ring structure.

2. **Analyzing Each Option**:
- **Option A: Water (H2O)**:
- Water molecules exhibit hydrogen bonding, but this bonding is between different water molecules (intermolecular hydrogen bonding). Therefore, water does not show intramolecular hydrogen bonding.

- **Option B: Hydrogen Fluoride (HF)**:
- Similar to water, HF also exhibits hydrogen bonding between different HF molecules. Thus, it does not show intramolecular hydrogen bonding.

- **Option C: Para-Nitro Phenol**:
- In para-nitro phenol, the nitro group and the hydroxyl group are positioned far apart on the benzene ring. Therefore, hydrogen bonding occurs between different para-nitro phenol molecules (intermolecular), not within the same molecule.

- **Option D: CCl3CHOH**:
- In this molecule, the hydroxyl group (OH) can potentially form a hydrogen bond with the electronegative chlorine atom (Cl) within the same molecule. This indicates the presence of intramolecular hydrogen bonding.

3. **Conclusion**:
- After analyzing all the options, we find that **CCl3CHOH** is the only species that shows intramolecular hydrogen bonding.

### Final Answer:
**CCl3CHOH** shows intramolecular hydrogen bonding.

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