Question

Aqueous tension is dependent on:
A.Volume
B.Pressure
C.Temperature
D.Weight of gas

Answer 1

Hint: At the liquid air interfaces, surface tension occurs as a result of greater attraction of liquid molecules to each other than to the attraction of liquid molecules to air. Due to surface tension, the liquid surface gets shrinked into the minimum surface area possible. Whereas aqueous tension is pressure exerted by water vapour.

Complete step by step answer:
Aqueous tension is defined as the partial pressure exerted by the water vapour, present in the most gas. The most gas is produced when the gas is collected over the water. In this situation the gas is moist due to the presence of small quantities of water vapour caused by the evaporation. Therefore, the total pressure that would be exerted on the surface above water can be expressed as:
Pressure exerted by most gas = pressure exerted by dry gas + less pressure exerted by water vapour (also known as vapour pressure)
i.e. ${P_{(moist)}} = {P_{(dry{\text{ gas}})}} + {P_{(water{\text{ vapor}})}}$
Thus, this total pressure exerted by the most gas is the combined pressure exerted by the dry gas and the water vapors.
However the partial pressure exerted by the water vapor is called aqueous tension.
i.e. ${P_{(water{\text{ vapor}})}} = aqueous{\text{ tension}}$
Therefore, we can say that extension is directly dependent on the vapour pressure.
So, it is fact to be noted that aqueous tension is dependent on temperature. It is independent of volume and pressure.

Hence, the correct option is (C) i.e temperature.

Additional information:
When the gas is collected over the water, it becomes moist due to the presence of small quantities of water vapors caused by evaporation. Then the pressure exerted by moist gas is equal to the sum of pressure exerted by dry gas and pressure of water vapour (aqueous tension).
i.e. ${P_{moist}} = {p_{dry}} + f(aqueous{\text{ tension}})$
or ${P_{dry}} = {P_{moist}} - f(aqueous{\text{ tension}})$
This is the reason, aqueous tension should be subtracted from total pressure to get pressure from dry gas.

Note:
Surface tension is simply the pressure exerted by saturated water vapour. It is independent of the amount of liquid, shape or volume of the container etc. Aqueous tension, being vapour pressure is constant at a given temperature and the value increases with increase in temperature.