Question

Which of the following has less hydrogen bonding $\mathrm{S}-\mathrm{H}$ or $\mathrm{O}-\mathrm{H}$?

Answer 1

Hydrogen bonding:

• Dipole-Dipole interaction between a hydrogen atom attached to an electronegative atom and another electronegative atom that lies close to the hydrogen atom is called hydrogen bonding.
• In water molecules (${\mathrm{H}}_2\mathrm{O}$), for example, hydrogen covalently bound to the electronegative oxygen atom show interactions with the oxygen atom of another ${\mathrm{H}}_2\mathrm{O}$ molecule, hence, hydrogen bonding occurs in water molecules.

Hydrogen bonding $\mathrm{S}-\mathrm{H}$ or $\mathrm{O}-\mathrm{H}$:

• Higher the electronegativity of the atom attached to hydrogen, more is the polarization of the molecule and hence strong hydrogen bonding.
• The hydrogen atom becomes positively charged and the electronegative atom becomes negatively charged due to polarization.

(Hydrogen bonding in water)

• In the case of $\mathrm{S}-\mathrm{H}$ and $\mathrm{O}-\mathrm{H}$ oxygen is more electronegative than Sulphur therefore polarization occurs more in the case of $\mathrm{O}-\mathrm{H}$ and hence $\mathrm{O}-\mathrm{H}$ has more hydrogen bonding as compared to $\mathrm{S}-\mathrm{H}$.

Therefore S-H has less H-bonding as compared to O-H.