colorless gas

Clear airborne substance

A colorless gas is one that cannot be seen—transparent to the eye, like air itself.

The phrase appears constantly in chemistry and safety contexts to describe substances like oxygen, nitrogen, hydrogen, and carbon monoxide: Radon is a colorless, odorless gas that can accumulate in basements.

The descriptor matters because visibility affects detection of leaks or contamination.

Related

lighter than air · asphyxiant · inert · helium · tasteless · refrigerant · nitrogen · carbon dioxide · neon · toxic gas · gas mask · compressible · oxygen · industrial use · boiling point · fuel source · propane tank · pollutant

Opposites
visibility/color

colorless gaschlorine gas

Reactive halogen in gaseous state

nitrogen dioxide · yellow smoke · black smoke

physical state

colorless gassolid

Firm matter state

liquid

visibility/appearance

colorless gascolored smoke

Pigmented vapor or fumes

black smoke · neon light

Family

color

Familiarity
Top 200,000
Profile
Known to kids · Used worldwide · Timeless · Concrete · Everyday, not technical · Rated G