Question

The vapour pressure of a given liquid will decrease if,
A) surface area of liquid will decreased
B) the volume of liquid in the container is decreased
C) the volume of the vapour phase is increased
D) the temperature is decreased

Answer 1

Hint: The tendency of a substance to transform into a gaseous or vapour state is measured by vapour pressure, which rises with temperature.

Complete answer: Let us consider the different options,
We know that surface area has no influence on the vapour pressure. Surface area is an extensive property but vapour pressure is an intensive property. We should remember that, the power of the intermolecular force at the surface, on the other hand, will have a direct impact on the surface stress, which is inversely proportional to the vapour pressure. That is, higher surface tension, lower vapour pressure, and higher intermolecular force strength. This shows that the vapour pressure of a given liquid will decrease if the surface area of liquid will decrease.
Now, let’s consider the other options,
The heavier the intermolecular forces that hold the material together, the less quickly the surface particles can vaporise, because the denser the condensed phase, the harder it is for the surface particles to evaporate. As a result, as liquid density rises, the vapour pressure above the liquid falls. If the amount of liquid in the container is reduced, the vapour pressure of the liquid would rise. Hence, the headspace volume reduces, and since there is less room for gas particles to evaporate and exert a vapour effect, the vapour pressure rises. We also know that, as seen on most phase diagrams, increasing temperature increases vapour pressure. Hence, the rest of the options are incorrect.
Therefore, the correct option is (A) surface area of liquid will decrease.

Note:
Remember that surface area has no influence on the vapour pressure. Also that higher surface tension, lower vapour pressure, and higher intermolecular force strength.