Nitrogen and oxygen combine to form many oxides. In some oxides, 14 g of nitrogen combine with either 16 g of oxygen or 32 g of oxygen. In some other oxides, 28 g of nitrogen combine with 16, 48, or 80 g of oxygen, (i) What are the formulae of the oxides ? (ii) What law of chemical combination does the formation of these compounds illustrate ?

Answer

`NO, NO_(2), N_(2)O, N_(2)O_(3), N_(2)O_(5)`; Law of multiple proportions

Explanation

In the given compounds, nitrogen and oxygen combine as follows :

Let us take a fixed mass say 28 g of nitrogen. The weights of oxygen combining with 28 g of nitrogen in these compounds will be as follows :

The ratio of weights of oxygen combining with 28 g of nitrogen are `2 : 4 : 1 : 3 : 5` which is a simple whole number ratio. Hence, the formation of these compounds illustrate law of multiple proportions.
Since, the atomic mass of nitrogen is 14 and that of oxygen is 16, the number of atoms of N and O in these compounds and their formulae can be obtained as follows :

Thus, the formulae of the given oxides are `NO, NO_2, N_2O, N_2O_3` and `N_2O_5`.