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
7.2 Water
A major part of all living organisms is made up of water. Human body has about $65\% $ and some plants have as much as $95\% $ water.
Physical Properties:
1. The unusual properties of water in the condensed phase (liquid and solid states) are due to the presence of extensive hydrogen bonding between water molecules. This leads to high freezing point, high boiling point, high heat of vaporisation and high heat of fusion in comparison to $H_2S$ and $H_2Se$.
2. Colourless, Odourless, Freezing point ${0^ \circ }C$, boiling point ${100^ \circ }C$ at $1$ atm pressure.
3. Maximum Density is $1.00\ gm cm^{-3}$ at ${4^ \circ }C$.
4. Water is polar molecule having high dielectric constant. i.e., $K=81$ at $298\ K$ temperature.
