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

🧠 Compare $\mathrm{H_2O}$ and $\mathrm{H_2S}$: water's high boiling point (373 K) is due to extensive hydrogen bonding. Sulfur is not electronegative enough to support H-bonding.

🗺️ Key difference:

• $\mathrm{H_2O}$: O is highly electronegative → strong O–H···O H-bonds → high bp = 373 K
• $\mathrm{H_2S}$: S is not electronegative enough → no H-bonding → only weak van der Waals forces hold molecules together

Expected boiling point of $\mathrm{H_2S}$:

Without H-bonding, $\mathrm{H_2S}$ relies on dispersion forces only. bp($\mathrm{H_2S}$) ≈ 213 K (−60 °C), which is significantly below 300 K.

⚡ The anomalously high bp of $\mathrm{H_2O}$ compared to $\mathrm{H_2S}$, $\mathrm{H_2Se}$, and $\mathrm{H_2Te}$ is direct evidence of hydrogen bonding.

$\boxed{\text{Answer: Less than 300 K}}$