For the solution of the gases w, x, y and z in water at 298K, the Henrys law constants (KH) are 0.5, 2, 35 and 40 kbar, respectively. The correct plot for the given data is :-

Solutions PYQ — JEE Main 2019 · 8 Apr · Shift 2 · Q1 with Solution

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Correct answer: A

Henry’s law relation

For a gas dissolved in water, $p = K_H x$ where:
- $p$ = partial pressure of gas
- $x$ = mole fraction of gas in solution
- $K_H$ = Henry’s law constant
Meaning of $K_H$

From $x = \frac{p}{K_H}$ we see that for a given pressure, larger $K_H$ means smaller solubility.

So, solubility order is inverse of $K_H$ .
Given values
- For $w$ : $K_H = 0.5$ kbar
- For $x$ : $K_H = 2$ kbar
- For $y$ : $K_H = 35$ kbar
- For $z$ : $K_H = 40$ kbar
Compare solubilities

Since smaller $K_H$ means greater solubility, $w > x > y > z$ in solubility.
Compare slopes if graph is $p$ vs $x$

From $p = K_H x$ slope $= K_H$ .

Hence slope order is $z > y > x > w$ because $40 > 35 > 2 > 0.5$
Correct plot

Therefore, the correct graph must show straight lines through origin with increasing slope in the order: $w < x < y < z$ (in terms of slope), or equivalently, solubility order: $w > x > y > z$

Thus, the correct option is A.