Which one shows maximum hydrogen bonding ?

Options

A. `H_2O`
B. `H_2Se`
C. `H_2S`
D. `HF`

Explanation

To determine which compound shows maximum hydrogen bonding among the given options (water, hydrogen selenide, hydrogen sulfide, and hydrogen fluoride), we will analyze the compounds based on the principles of electronegativity and atomic size.

### Step-by-Step Solution:

1. **Understanding Hydrogen Bonding**:
Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative atom (like oxygen, nitrogen, or fluorine), which creates a strong dipole-dipole interaction with another electronegative atom.

**Hint**: Recall that hydrogen bonding strength is influenced by the electronegativity of the atom to which hydrogen is bonded.

2. **Identify the Atoms in Each Compound**:
- Water (H₂O): Hydrogen is bonded to Oxygen.
- Hydrogen Selenide (H₂Se): Hydrogen is bonded to Selenium.
- Hydrogen Sulfide (H₂S): Hydrogen is bonded to Sulfur.
- Hydrogen Fluoride (HF): Hydrogen is bonded to Fluorine.

**Hint**: List the electronegativities of the atoms involved to compare their ability to form hydrogen bonds.

3. **Electronegativity and Atomic Size**:
- Electronegativity increases across a period and decreases down a group in the periodic table.
- For the elements in question:
- Oxygen (O) has a high electronegativity (3.44).
- Sulfur (S) has a lower electronegativity (2.58).
- Selenium (Se) has an even lower electronegativity (2.55).
- Fluorine (F) has the highest electronegativity (3.98).

**Hint**: Remember that higher electronegativity leads to stronger hydrogen bonds.

4. **Comparing the Compounds**:
- Water (H₂O) has strong hydrogen bonding due to the high electronegativity of Oxygen.
- Hydrogen Fluoride (HF) has the strongest hydrogen bonding because Fluorine is the most electronegative element.
- Hydrogen Sulfide (H₂S) and Hydrogen Selenide (H₂Se) have weaker hydrogen bonds due to lower electronegativities of Sulfur and Selenium.

**Hint**: Focus on the electronegativity values to determine which compound will have the strongest hydrogen bonds.

5. **Conclusion**:
Based on the analysis, Hydrogen Fluoride (HF) shows maximum hydrogen bonding due to the high electronegativity of Fluorine compared to the other elements.

**Final Answer**: The compound that shows maximum hydrogen bonding is **Hydrogen Fluoride (HF)**.