Final answer:
The vapor pressure of a liquid increases with temperature and the normal boiling point is when vapor pressure equals 1 atm. The vapor pressure can be influenced by intermolecular forces and surrounding atmospheric pressure, making it variable and measurable. Option A is correct.
Step-by-step explanation:
The vapor pressure of a liquid increases as the temperature increases, and it is dependent on temperature. The normal boiling point of a liquid is the temperature at which its vapor pressure equals 1 atm (101.3 kPa). At this point, the vapor pressure of the liquid is equal to the atmospheric pressure, indicating that the liquid has reached its boiling point.
Atmospheric pressure can vary based on location, which implies that the boiling point of a liquid can change with surrounding pressure. Furthermore, the strength of intermolecular forces in the liquid can affect the vapor pressure, with stronger forces typically resulting in lower vapor pressures at a given temperature.
It is incorrect to say that the vapor pressure of a liquid decreases with increasing temperature or that it is independent of temperature. Vapor pressure can indeed be measured, and is not a constant value that cannot be obtained. Finally, vapor pressure is equal to one atmosphere at the normal boiling point, which confirms one of the statements from the student's question.