A colloidal suspension in which gas is the suspending medium is called an aerosol.

Here's a breakdown:

* Colloidal suspension: A mixture where tiny particles are dispersed evenly throughout a medium. These particles are larger than molecules but smaller than what you can see with the naked eye.

* Aerosol: Specifically refers to a colloidal suspension where the dispersing medium is a gas.

Examples of aerosols include:

* Fog: Water droplets suspended in air

* Smoke: Solid particles suspended in air

* Clouds: Water droplets or ice crystals suspended in air

* Hairspray: Tiny droplets of liquid suspended in air

* Dust: Solid particles suspended in air

Let me know if you have any other questions!