The correct option is D Polar nature of halogen acid
(a) High boiling point of H2O is due to intermolecular H - bonding.
(b ) Glycerol has 3 −OH groups and these three are involved in H-bonding. This means that the intermolecular forces are much greater because of these hydrogen bonds. Therefore, the viscosity is high.
(c) The solubility of a substance in water depends on its polar nature. NH3 molecules, being polar, readily bond with H2O molecules by H-bonding, making it water soluble.
(d) Polar nature of halogen acids (HX) is due to the electronegativity difference between H and halogen atoms. Except Fluorine, other halogens do not show H-bonding due to their large sizes and diffused electrons, reducing the charge density that is required for H-bonding.