Question

Study the graph between partial pressure and mole fraction of some gases and arrange the gases P, Q, R, and S dissolved in H2O, in the decreasing order of their KH values.

• A. \( S>P>R>Q \)
• B. \( R>Q>P>S \)
• C. \( P>R>S>Q \)
• D. \( Q>R>P>S \)

Hint:

In Henry’s law, the solubility of a gas is inversely proportional to the value of the Henry’s law constant \( K_H \). A steeper slope in a plot of partial pressure vs mole fraction implies a lower \( K_H \) and thus a higher solubility.

Answer 1

The Correct Option is A

The given problem involves the interpretation of a graph showing the relationship between partial pressure and mole fraction for different gases (P, Q, R, and S) dissolved in water (H\(_2\)O). 
The graph represents Henry’s law, which states that the solubility of a gas in a liquid is directly proportional to its partial pressure, and the proportionality constant is the Henry’s law constant \( K_H \). 
From the graph: - The steeper the slope, the lower the Henry’s law constant \( K_H \), indicating a greater solubility. 
- Conversely, the flatter the slope, the higher the \( K_H \), indicating a lower solubility. 
By analyzing the graph, we observe that: - Gas S has the flattest slope, which corresponds to the highest \( K_H \) value (least soluble). 
- Gas P has a steeper slope than gas S but less steep than gases R and Q. 
- Gas R has a steeper slope than gas P, indicating a lower \( K_H \) than gas P but higher than gas Q. - Gas Q has the steepest slope, which indicates the lowest \( K_H \) value (most soluble). 
Thus, the gases should be arranged in decreasing order of \( K_H \) as: \[ S>P>R>Q \] Hence, the correct answer is \( (A) \).