KCET 2021 Chemistry Solved Paper

The correct order of boiling point of given hydrides is as follows H2O>HF>NH3
Strength of H-bonding depends upon size and electronegativity of the atom. Smaller the size of the atom, greater is the electronegativity and stronger is the H-bonding.
But each H2O molecule has two hydrogen atom, whereas each HF molecule has only one hydrogen atom.
∴ Hydrogen bonding is more strong in H2O molecules. While NH3 molecules due to less electronegativity of 'N′ atom than 'F′ atom is less polar and hence, have weak hydrogen bonding than HF molecules.