55. Why does water show high boiling point as compared to hydrogen sulphide? Give reasons for your answer.
Water show high boiling point as compared to hydrogen sulphide due to high electronegativity of oxygen (EN=3.5). Water undergoes extensive H-bonding as a result of which water exists as associated molecule.
For breaking these hydrogen bond, a large amount of energy is needed and hence the boiling point of H2O to high.
In other words, due to lower electronegativity of S (EN=2.5), hydrogen sulphide do not undergo H-bonding. Consequently, H2S exists as discrete molecule and hence its boiling point is much lower than that of H2O. Thats why H2S is a gas at room temperature.