What effect does lowering the pressure on the surface of water have on the boiling point?

It increases the boiling point
It decreases the boiling point
the boiling point remains the same

Raising the pressure increases the boiling point. (The automobile radiator works that way).

Lowering the pressure decreases the boiling point.

Lowering the pressure on the surface of water decreases the boiling point. This is known as the principle of Le Chatelier's principle, which states that a system at equilibrium will adjust to counteract any changes imposed upon it. In the case of water, when the pressure is reduced, the equilibrium between the liquid and vapor phases is disrupted. The molecules in the liquid phase have a greater tendency to escape as vapor to restore the equilibrium. As a result, the boiling point decreases, and the water boils at a lower temperature. This is why water boils at a lower temperature at higher altitudes where the atmospheric pressure is lower.