(1) The mixing of different gases in air is a natural process that takes place continuously.
(2) Smoke coming out of factories is seen only near the mouth of chimneys. After rising high it mixes up with air and vanishes out. This happens becaues of diffusion or gases.
(3) When salt solution kept in water this makes the whole solution salty after some times. This happens because of diffusion in liquids.
(4) Alloys are possible to get prepared because of the diffusion of solid into solid. Bronze steel, brass are examples of alloy
