To determine which compound exhibits the strongest hydrogen bonding, we need to analyze the options provided: Water (H₂O), Ammonia (NH₃), Hydrogen Fluoride (HF), and Hydrogen Sulfide (H₂S).
### Step-by-Step Solution:
1. **Understanding Hydrogen Bonding**:
- Hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like N, O, or F) interacts with another electronegative atom. The strength of hydrogen bonding is influenced by the electronegativity of the atoms involved.
2. **Evaluating the Options**:
- **Water (H₂O)**: In water, hydrogen is bonded to oxygen, which is quite electronegative. Water does exhibit hydrogen bonding, but we need to compare its strength with the other options.
- **Ammonia (NH₃)**: In ammonia, hydrogen is bonded to nitrogen. Nitrogen is also electronegative, and ammonia can form hydrogen bonds, but again, we need to compare it with the other compounds.
- **Hydrogen Fluoride (HF)**: In HF, hydrogen is bonded to fluorine, which is the most electronegative element. This results in a very strong hydrogen bond due to the significant electronegativity difference between hydrogen and fluorine.
- **Hydrogen Sulfide (H₂S)**: In hydrogen sulfide, hydrogen is bonded to sulfur, which is less electronegative than oxygen and nitrogen. Therefore, the hydrogen bonding in H₂S is weaker compared to the other compounds.
3. **Comparing Electronegativity**:
- The electronegativity values (on the Pauling scale) are approximately:
- Fluorine (F) = 4.0
- Oxygen (O) = 3.5
- Nitrogen (N) = 3.0
- Sulfur (S) = 2.5
- The electronegativity difference between hydrogen and fluorine is the largest, leading to the strongest hydrogen bond in HF.
4. **Conclusion**:
- Based on the analysis, HF has the strongest hydrogen bonding due to the high electronegativity of fluorine compared to the other elements involved in the other compounds.
### Final Answer:
The strongest hydrogen bonding is shown by **Hydrogen Fluoride (HF)**.
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