What happens when the vapor pressure of a liquid equals atmospheric pressure?

When the vapor pressure of a liquid equals the atmospheric pressure, the liquid begins to boil. Boiling is the process where a liquid turns into vapor, and it occurs at a specific temperature known as the boiling point. At this temperature, the molecules in the liquid have enough energy to overcome intermolecular forces and enter the gas phase.

When vapor pressure rises to match atmospheric pressure, it indicates that there is sufficient energy and kinetic activity among the liquid molecules for them to escape into the vapor phase, leading to bubbling and boiling throughout the liquid. This is a fundamental principle of physical chemistry and thermodynamics, illustrating the relationship between vapor pressure, temperature, and phase changes.

In terms of other options, instantaneous evaporation does not occur at a specific pressure level, and solidification would require temperature reduction rather than a change in pressure. Additionally, remaining unchanged does not apply when a liquid reaches its boiling point under the influence of atmospheric pressure; the phase transition is dynamic and active, not static.