HF has highest boiling point among hydrogen halides, because it has:

Options

A. strongest hydrogen bonding
B. lowest ionic character
C. strongest van der Waal’s interactions
D. lowest dissociation enthalpy

Explanation

To determine why HF (Hydrogen Fluoride) has the highest boiling point among hydrogen halides, we need to analyze the factors that influence boiling points, particularly focusing on intermolecular forces.

### Step-by-Step Solution:

1. **Understanding Boiling Point**:
- The boiling point of a substance is influenced by the strength of intermolecular forces. The stronger the intermolecular forces, the higher the boiling point.

**Hint**: Remember that boiling point is related to how strongly molecules attract each other.

2. **Types of Intermolecular Forces**:
- The main types of intermolecular forces include Van der Waals forces, dipole-dipole interactions, and hydrogen bonding. Among these, hydrogen bonding is the strongest.

**Hint**: Identify the different types of intermolecular forces and their relative strengths.

3. **Electronegativity of Elements**:
- In HF, the electronegativity difference between hydrogen (H) and fluorine (F) is significant. Fluorine is highly electronegative, which leads to a strong dipole moment in the HF molecule.

**Hint**: Consider how electronegativity affects the polarity of a molecule.

4. **Formation of Hydrogen Bonds**:
- Due to the high electronegativity of fluorine, HF molecules can form strong hydrogen bonds with each other. The partial negative charge on fluorine (δ-) and the partial positive charge on hydrogen (δ+) allow for strong attractions between HF molecules.

**Hint**: Think about how the charges in the molecule contribute to intermolecular attractions.

5. **Comparison with Other Hydrogen Halides**:
- Other hydrogen halides (HCl, HBr, HI) do not form hydrogen bonds as strong as HF because they have lower electronegativity differences and hence weaker dipole moments. Therefore, their boiling points are lower than that of HF.

**Hint**: Compare the properties of HF with those of other hydrogen halides to understand the differences in boiling points.

6. **Conclusion**:
- The strongest intermolecular force in HF is hydrogen bonding, which is responsible for its highest boiling point among the hydrogen halides.

**Final Answer**: The correct option is **strongest hydrogen bonding**.