Water

Molecular formula: H₂O

Molecular weight: 18

Introduction

            From the origin of the earth water is present on the earth. In Hindu mythology water is an element of constituent of life. But modern science has revealed that water is compound of Hydrogen and oxygen combined in 1:8 ratios.

Water has three states: solid, liquid and gas (vapour) according to the temperature. At normal temperature it is found in liquid state but when it is cooled less than 0 C, it becomes ice (solid state) and at higher temperatures it becomes vapour (gas state). Water has a special property. When heated from 0C to 4C its density increases and occupies less volume. This is known as anomalous property of water.

            Water is known as universal solvent since it dissolves many substances. Without water life is not possible. Water content in human body is 70%, in fishes 80%, in vegetables 90-95% by weight.

            Water is used in drinking, cleaning utensils, washing. Cooking, cooling in industries, etc. For different purposes water is used in pure form. For the chemical reactions in the lab, it is used in very pure form.