If applied pressure on a saturated vapor is decreased, then ____.

When the applied pressure on a saturated vapor is decreased, the state of the vapor can change significantly. In a saturated condition, the vapor is at equilibrium with its corresponding liquid phase. Reducing the pressure lowers the saturation pressure, meaning that the vapor can no longer remain in a saturated state at that pressure.

As a result, some of the vapor will condense into liquid, which is a characteristic behavior of phase changes in thermodynamics. When the pressure is reduced, the vapor tries to reach a new equilibrium with the liquid phase, leading to condensation as some of the vapor turns back into liquid to match the new lower saturation pressure.

Thus, the situation where pressure is decreased involves a balance between the vapor and liquid phases, and the most immediate and direct consequence is the condensation of some vapor into liquid. Hence, the correct answer encompasses the process that occurs when pressure is altered, confirming that some vapor will condense, which supports the idea that the vapor cannot sustain saturation at the lower pressure.