Question

Compare the structures of ice and water with respect to the number and geometry of hydrogen bonds.

Short answer

Each water molecule in ice is hydrogen-bonded to its neighbouring 4 water molecules to form crystals of ice. In liquid water, each molecule is H−bonded to approximately 3.4 other water molecules.

Step-by-step solution

Step 1

Water molecule is formed by covalent bonding between two hydrogens and one oxygen atom forming one molecule of water. In the case of ice, the structure is rigid lattice like a giant molecule.

Step 2

The kinetic energy of atoms in a molecule of water is high which causes continuous formation and breaking of bonds therefore permanent bonds are not formed. When water freezes, it creates a tetrahedral structure in which each water molecule makes a hydrogen bond with four other water molecules. This tetrahedral structure collapses when water is in liquid form; still, it establishes hydrogen bonds but is less structurally firm and more dense.