Question

The low density of ice compared to water is due to:
A.Hydrogen bonding interactions
B.Dipole-Dipole interactions
C.Dipole-induced dipole interactions
D.Induced dipole- induced dipole interactions

Answer 1

Intermolecular forces are the forces of attraction between and repulsion between atoms and molecules in gas, liquid and solid. Intermolecular forces are of different types.

Complete step by step answer:
Intermolecular forces are of different types. Attractive intermolecular forces are known as Van der waals forces. That include dipole-dipole forces, dipole-induced dipole force, induced dipole-induced dipole forces.
Hydrogen bond is a special type of dipole-dipole interaction between the molecules. There are certain criteria for the formation of hydrogen bond. There must be a highly electronegative atom like F, O, or N in the compound. When hydrogen Is attached to such an electronegative atom, partial charge separation happens and the molecule becomes polar. The positively charged Hydrogen interact with the negative end of the neighboring molecule forming a bridge between the two molecules.
Hydrogen bonding is different. Intermolecular hydrogen bonding, Intramolecular hydrogen bonding.
Intermolecular hydrogen bonding is present between different molecules of the same substance or different substance. It causes association of molecules into clusters. Extensive network of Hydrogen bonds causes the molecule to have a high boiling point. Examples for molecules showing intermolecular hydrogen bonding include water, Ammonia.
Extensive network of Hydrogen bonding is the reason for the anomalous behavior of water. Water shows unexpectedly high boiling points and density of ice is less than water.
Through intermolecular Hydrogen Bonding, each molecule in water gets connected to four other water molecules in a tetrahedral manner. In Ice, the continuous tetrahedral pattern leads to a rather open hexagonal three-dimensional structure with several cavities. The large space within the ice gives ice a lower density than water. Thus, ice floats on the water.

Hence, the correct answer is Option (A) i.e. Hydrogen bonding interactions.

Note: Students may get confused with Intermolecular and Intramolecular Hydrogen Bonding. Intermolecular Hydrogen Bonding is present between different molecules of the same substance. Intramolecular Hydrogen Bonding is present within the same molecule. Intramolecular Hydrogen bonding is Present in O-nitrophenol, Salicylic acid. Intramolecular Hydrogen bonding does not cause the association of molecules. Among Intermolecular Hydrogen Bonding and Intramolecular Hydrogen Bonding, the former one is showing high Boiling point.