Why is air called a mixture?

Made of many gases:

Air contains nitrogen (~78%), oxygen (~21%), carbon dioxide (~0.03%), argon, water vapor, and other gases.

No fixed ratio:

• The proportion of gases can vary from place to place (e.g., more water vapor in humid areas).

• In a compound, elements combine in a fixed ratio, but air does not follow this rule.

No chemical reaction:

• The gases in air are just physically mixed, not chemically bonded.

• Each gas retains its own properties (e.g., oxygen supports burning, nitrogen does not).

Can be separated:

Components of air can be separated by physical methods like fractional distillation of liquid air.

Final Answer: Air is called a mixture because it is made of several gases present in varying proportions, not chemically combined, and each gas retains its own properties.