Hydrogen
1.0 Basic Information
2.0 Atomic and Physical Properties of Hydrogen (reference: NCERT)
3.0 Dihydrogen
4.0 Physical Properties
5.0 Chemical Properties
6.0 Uses of Dihydrogen
7.0 Compounds of Hydrogen
8.0 Hard and Soft Water
9.0 Hydrogen Peroxide
10.0 Volume strength of Hydrogen Peroxide
7.3 Structure of water
In the gas phase water is a bent molecule with a bond angle of ${104.5^ \circ }$ and $O–H$ bond length of $95.7\ pm$ as shown in $(a)$. It is a highly polar molecule, $(b)$. Its orbital overlap picture is shown in $(c)$.
In the liquid phase water molecules are associated together by hydrogen bonds. The crystalline form of water is ice. At atmospheric pressure ice crystallizes in the hexagonal form, but at very low temperatures it condenses to cubic form. Density of ice is less than that of water. Therefore, an ice cube floats on water. In winter season ice formed on the surface of a lake provides thermal insulation which ensures the survival of the aquatic life.
