What does an increase in pressure do to the boiling point of a liquid?

An increase in pressure causes the boiling point of a liquid to significantly increase. This occurs because the boiling point is defined as the temperature at which a liquid's vapor pressure equals the external pressure surrounding the liquid. When the pressure surrounding the liquid is raised, the molecules require more energy (in the form of heat) to reach the vapor pressure necessary to boil. Thus, the temperature must increase for the liquid to boil under higher pressure conditions. This principle is fundamental in various applications of refrigeration and boiling processes, particularly in devices like pressure cookers, which utilize increased pressure to raise the boiling point for faster cooking.