For a solution of the gases A, B, C and D in water at 298 K, the values of Henry's law constant (K H ) are 30.40, 2.34, 1.56 × 10⁻⁵ and 0.513 k bar respectively. In the given graph, the lines marked as 'p' and 's' correspond respectively to :

Solution

Chemistry ma’am · 3 steps

In Henry's law, K_H sets the height of the line: the biggest K_H sits on top, the smallest at the bottom.

1. Henry's law. The partial pressure of a gas over its solution is p = K_H x_(gas), and in a two-component solution x_(gas) = 1 - x_(H₂O).

   p = K_H(1 - x_(H₂O))

2. Read the graph. At any fixed x_(H₂O), a gas with a larger K_H shows a higher partial pressure, and its line also falls more steeply. So the top line has the largest K_H, and the nearly flat bottom line has the smallest K_H.

   Gas	K_H (kbar)	Rank	Line
   A	30.40	largest	p (top)
   B	2.34	second	q
   D	0.513	third	r
   C	1.56 × 10⁻⁵	smallest	s (flat, bottom)

3. So. Line p belongs to A and line s belongs to C, which is option (a).

The idea to keep. A larger K_H means a higher partial pressure for the same composition, so the gas is less soluble. On a p vs mole fraction graph, rank the lines by K_H from top to bottom.

Answer from the NTA final answer key. Solution by PrepWiser.