Question

If the pressure of dry gas is given by X and the total pressure is given by X + 3, then what is aqueous tension?

(a) 2

(b) X

(c) X + 2

(d) 3

This question was posed to me in a national level competition.

The origin of the question is States of Matter topic in division States of Matter of Chemistry – Class 11

Answer 1

The correct answer is:

(d) 3

Explanation: In this scenario, the total pressure is the sum of the pressure exerted by the dry gas (X) and the aqueous tension (the vapor pressure of water in the air).

So, if the total pressure is given by $X+3$ and the dry gas pressure is $X$, the difference between the total pressure and the dry gas pressure is the aqueous tension.

Therefore:

$$\text{Aqueous Tension}=(X+3)-X=3$$

Thus, the aqueous tension is 3.