Why is air considered as a mixture and not compound?
Air is considered as a mixture because it exhibits following properties:
- Each component present in air retains its properties.
- Each component can be separated by simple physical processes.
- The components do not have any fixed proportion. All gases are present in different amount. Example, in greener area—more oxygen and water vapour is present; near industrial area—air consists of lot of impurities and smoke suspended in it.
The properties of the constituents of air (oxygen, nitrogen, carbon dioxide etc.) are not changed. For example, pure oxygen is a supporter of combustion. Oxygen present in air also supports combustion. Pure carbon dioxide turns lime water milky. Carbon dioxide present in air also turns lime water milky.