Strongest hydrogen bonding is present in

Options

A. HF
B. HCl
C. HBr
D. HI

Answer

To determine which compound exhibits the strongest hydrogen bonding, we will analyze the given options based on the principles of hydrogen bonding.

### Step-by-Step Solution:

1. **Understanding Hydrogen Bonding**:
Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative atom (like fluorine, oxygen, or nitrogen) and experiences an attraction to another electronegative atom.

2. **Analyzing the Options**:
- **Option 1: HF (Hydrogen Fluoride)**:
- Fluorine has a very high electronegativity (approximately 4.0), which means it can create a strong hydrogen bond with hydrogen.
- **Option 2: HCl (Hydrogen Chloride)**:
- Chlorine is less electronegative than fluorine (approximately 3.0), resulting in weaker hydrogen bonding compared to HF.
- **Option 3: HPF (Hydrogen Phosphide)**:
- Phosphorus is even less electronegative (approximately 2.1), leading to very weak hydrogen bonding.
- **Option 4: HI (Hydrogen Iodide)**:
- Iodine is also less electronegative (approximately 2.5), which results in weak hydrogen bonding.

3. **Comparing the Strength of Hydrogen Bonds**:
- Among the options, HF has the strongest hydrogen bond due to the high electronegativity of fluorine. The other options (HCl, HPF, HI) have weaker hydrogen bonds because they involve less electronegative atoms.

4. **Conclusion**:
- The strongest hydrogen bonding is present in **HF (Hydrogen Fluoride)**.

### Final Answer:
The strongest hydrogen bonding is present in **HF**.