Question

The reduced vapor pressure at high altitudes causes a liquid to boil at a temperature.

A. Lower
B. Higher

Answer 1

At higher altitudes (and thus lower atmospheric pressures), water boils at a lower temperature. This is because the lack of vapor pressure at that altitude doesn't constrain the speed of the molecules with barometric pressure. Therefore, the water begins boiling at a lower temperature. This is often a disadvantage because even if the water is boiling, it won't be hot enough for meals (which is why heat and temperature are distinct). That's why we have pressure cookers, which manage to keep a stable boiling point.
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Answer 2

Lower Temperature

Step-by-step explanation:

The boiling point is defined as the temperature at which the vapor pressure of a given liquid becomes equal to the external pressure or atmospheric pressure. Boiling point is mainly effected by following factors:

1) Inter-Molecular Interactions:

Greater the intermolecular interactions greater will be the boiling point because more energy is required to overcome these intermolecular interactions.

Example:

Water = 100 °C

Diethyl ether = 34.5 °C

Water requires more energy because it contains hydrogen bond interactions which are considered the strongest intermolecular interactions. While, Diethyl ether lacks Hydrogen bondings.

2) External Pressure:

The boiling point also varies with changing the external pressure for the same solvent. Greater the external pressure greater will be the boiling points and vice versa.

Example:

Water:

External Pressure Boiling Point

1 atm 100 °C

0.921 atm 98 °C

0.425 atm 72 °C