What do you call the temperature at which the vapor pressure of a liquid is equal to atmospheric pressure?

The temperature at which the vapor pressure of a liquid equals atmospheric pressure is known as the boiling point. At this critical temperature, the liquid transitions to a gas, forming bubbles within the liquid. This process occurs because the molecules in the liquid gain enough energy to escape into the air as vapor.

In practical terms, the boiling point varies depending on the surrounding atmospheric pressure—at higher elevations, where atmospheric pressure is lower, liquids can boil at lower temperatures than at sea level. Understanding the concept of boiling point is crucial in fire safety and related applications, as it helps in assessing flammability and the behavior of various liquids when heated.

The other terms, such as freezing point and melting point, pertain to phase changes involving solids and liquids at temperatures above and below melting/freezing conditions, respectively. The flash point refers to the lowest temperature at which vapors of a substance will ignite when exposed to a flame, which is distinctly different from the boiling point concept. Thus, boiling point is the proper term to describe the balance between vapor pressure and atmospheric pressure leading to the phase transition from liquid to gas.