Question

What is the difference in bonding of hydrogen in H20 and the subsequent hydrides of the group which makes its boiling point higher than its subsequent of the group ?

Answer 1

Among the hydrides of group 16, H₂O has unusually high melting and boiling point.
Reason- It is due to association of H₂O molecules through hydrogen bonding. However, hydrogen bonding is not present in other hydrides. The intermolecular forces between the hydrides (except H₂O) are van der Waal's forces. These forces are weaker than hydrogen bonding, however these forces increases with increase in molecular size and therefore we see a regular trend of increase in melting point and boiling point after H₂O.