State and explain the law of multiple proportions.

Law of multiple proportions (John Dalton 1804) states that when two elements combine to form two or more compounds, the weight of one of the elements which combines with a fixed weight of the other, bears a simple whole number ratio. For example, hydrogen and oxygen combine to form two compounds H₂O (water) and H₂O₂(hydrogen peroxide). In water, Hydrogen 2 parts and oxygen 16 parts In hydrogen peroxide hydrogen 2 parts and oxygen 32 parts.
The weights of oxygen which combine with same weight of hydrogen in these two compounds bear a simple ratio 1 : 2. Nitrogen forms five stable oxides:
N₂O Nitrogen 28 parts Oxygen 16 parts
N₂O₂ Nitrogen 28 parts Oxygen 32 parts
N₂O₃ Nitrogen 28 parts Oxygen 48 parts
N₂O₄ Nitrogen 28 parts Oxygen 64 parts
N₂O₅ Nitrogen 28 parts Oxygen 80 parts
The weight of oxygen which combines with same weight of nitrogen in the five compounds bear a ratio 16 : 32 : 48 : 64 : 80 : or 1 : 2 : 3 : 4 : 5.