The temperature at which a substance in liquid state becomes gas is called its boiling point.

Here's a little more detail:

* Boiling point is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid, and the liquid changes into a vapor.

* This means that at the boiling point, bubbles of vapor form within the liquid and rise to the surface.

* The boiling point of a substance is affected by factors like atmospheric pressure.

Let me know if you have any other questions!