Question

Which of the following gases has the lowest solubility in water at 298 K?

• A. Argon
• B. Carbon dioxide
• C. Formaldehyde
• D. Methane
• E. Vinyl chloride

Hint:

Noble gases like argon have the lowest solubility in water because of their non-polar nature and the lack of significant interactions with water molecules.

Answer 1

The Correct Option is A

The solubility of gases in water can be understood in terms of Henry’s Law, which states that the solubility of a gas in a liquid is directly proportional to its partial pressure. Some gases have very low solubility due to their chemical properties.
- Argon (A): Argon is a noble gas, and noble gases have the lowest solubility in water due to their non-polar nature. This makes Argon the correct answer as it has the lowest solubility among the listed gases. - Carbon dioxide (B): Carbon dioxide dissolves readily in water due to its ability to react with water to form carbonic acid, which increases its solubility.
- Formaldehyde (C): Formaldehyde is polar and can easily dissolve in water due to its ability to form hydrogen bonds with water molecules. - Methane (D): While methane is non-polar, it still has a higher solubility than argon due to its smaller size and higher tendency to interact with water to a slight extent.
- Vinyl chloride (E): Vinyl chloride, although non-polar, is more soluble in water than argon.
Thus, the correct answer is (A) Argon, as it is a noble gas with the lowest solubility in water among the options listed.