Question

$X$, $Y$ and $Z$ in the above graph are

• A. $X = p_1 + p_2$, $Y = 1$, $Z = 0$
• B. $X = p_1 + p_2$, $Y= 0$, $Z = 0$
• C. $X = p_1 \times p_2$, $Y= 0$, $Z = 1$
• D. $X = p_1 - p_2$, $Y = 1$, $Z = 0$

Answer 1

Answer: (B)

Here, $X = P _{ T }= p _{1}+ p _{2}=$ Total pressure of the solution.
$p _{1}$ and $p _{2}$ is the partial pressure of component $1$ and $2$ respectively.
$Y = x _{2}=$ mole fraction of component $2$ in the liquid phase.
$Z = y _{2}=$ mole fraction of component $2$ in the vapour phase.
When mole fraction of component $2$ in the liquid phase is $0$ then mole fraction of component $2$ in the vapour phase is also $0$ which means the liquid is pure of component $1$ only.