Question

why is boiling point of H2S is lower than H2O??

Answer 1

In water H2O there is electrostatic attraction between partially positive hydrogen of one atom with partial negative oxygen (highly electronegative) of another atom which produces dipole-dipole interactions resulting hydrogen bonding. As these hydrogen bonds are strong in water, it requires high energy to break the bonds with high boiling point of

373 K.

While in hydrogen sulphide H2S, even though there are intermolecular forces of attraction between atoms, hydrogen bonding is not present. Hence the H2S requires less energy to break the bonds with low boiling point of 213 K.