Question

The following graph is obtained by taking partial pressure of HCl(g) on \(y\)-axis and mole fraction of HCl(g) in cyclohexane on \(x\)-axis. The slope (\(m\)) of the graph is

• A. Henry constant \((K_H)\) of cyclohexane
• B. \(K_H\) of HCl(g)
• C. Square root of \(K_H\) of HCl(g)
• D. \(\dfrac{1}{K_H(\mathrm{HCl})}\)

Hint:

Henry's law can be written as \[ \boxed{ p=K_Hx. } \] Thus, for a graph of \[ p \text{ versus } x, \] the slope is simply \[ \boxed{K_H.} \]

Answer 1

The Correct Option is B

Step 1: Recall Henry's law. Henry's law is given by \[ \boxed{ p=K_Hx, } \] where \[ p=\text{partial pressure of the gas}, \] and \[ x=\text{mole fraction of the gas dissolved in the liquid}. \]

Step 2: Compare with the graph. The graph is plotted with \[ y=p \] and \[ x=\text{mole fraction}. \] Hence, \[ y=K_Hx, \] which is the equation of a straight line passing through the origin. Therefore, the slope is \[ \boxed{K_H.} \] Since the gas is HCl, \[ \boxed{m=K_H(\mathrm{HCl}).} \] Therefore, the correct option is \(\boxed{(B)}\).