If the solubility of the given gases in water decreases in the order of formaldehyde, methane, vinyl chloride, argon.
Match List-I with List-II.
|
List-I Gas |
List-II \( K_H/k \) bar |
|
(A) Formaldehyde |
(I) 40.3 |
|
(B) Vinyl Chloride |
(II) 0.413 |
|
(C) Argon |
(III) \( 1.83 × 10^{-5} \) |
|
(D) Methane |
(IV) 0.611 |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
By Henry’s law, the partial pressure of a gas over a solution is proportional to its mole fraction in the solution, \( p = K_H\,x \). At a given pressure the solubility is therefore
\( \displaystyle x = \frac{p}{K_H} \)
so the higher the value of \( K_H \), the lower the solubility of the gas. A solubility order that decreases from formaldehyde to argon means that \( K_H \) increases in the same order: formaldehyde has the smallest \( K_H \) and argon the largest.
(A) Formaldehyde — This matches (III) \(1.83 × 10^{-5}\). It is the most soluble gas, so it has the smallest \( K_H \).
(B) Vinyl Chloride — This matches (IV) 0.611. It is third in solubility, so its \( K_H \) is larger than that of methane.
(C) Argon — This matches (I) 40.3. It is the least soluble, so it has the largest \( K_H \).
(D) Methane — This matches (II) 0.413. It is second in solubility, with the second smallest \( K_H \).
Shortcut: The most soluble gas, formaldehyde, must have the smallest \( K_H \), (III). Only Option (4) has (A)-(III).
NCERT (2026-27 edition):
Solubility of a Gas in a Liquid – …
