If the boiling point of H2O is 373 K, the boiling point of H2S will be :

Options

A. greater than 300 K but less than 373 K
B. equal to 373 K
C. more than 373 K
D. less than 300 K

Explanation

To determine the boiling point of H2S given that the boiling point of H2O is 373 K, we can analyze the molecular properties and intermolecular forces involved in both compounds.

### Step-by-Step Solution:

1. **Identify the Compounds**: We are comparing water (H2O) and hydrogen sulfide (H2S).

2. **Understand the Group**: Both oxygen (O) and sulfur (S) belong to Group 16 of the periodic table.

3. **Electronegativity Comparison**: Oxygen is more electronegative than sulfur. This means that in H2O, the oxygen atom attracts the bonding electrons more strongly than the sulfur in H2S.

4. **Molecular Size**: As we move down the group from oxygen to sulfur, the atomic size increases. Therefore, H2S has larger molecular size compared to H2O.

5. **Intermolecular Forces**:
- In H2O, strong hydrogen bonds form due to the high electronegativity of oxygen, which creates a significant partial negative charge on the oxygen and a partial positive charge on the hydrogen atoms. This leads to strong attractions between water molecules.
- In H2S, the intermolecular forces are primarily Van der Waals forces (dispersion forces), which are much weaker than hydrogen bonds.

6. **Boiling Point Implications**: Due to the strong hydrogen bonding in H2O, it requires more energy (higher temperature) to break these bonds for the substance to boil, resulting in a higher boiling point (373 K). In contrast, the weaker Van der Waals forces in H2S mean that it requires less energy to convert from liquid to gas, resulting in a lower boiling point.

7. **Conclusion**: The boiling point of H2S is significantly lower than that of H2O. Based on the analysis, the boiling point of H2S is approximately 373 K - 70 K = 303 K (or about 300 K).

### Final Answer:
The boiling point of H2S is approximately 300 K.

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