Question

For an ideal binary solution $\left(A\right)$ and $\left(B\right)$, $y_A$ is the mole fraction of $A$ in vapor phase. Which of the following plot should be linear?

• A. $P_{total}vs{y}_A$
• B. $P_{total}vs{y}_B$
• C. $\frac{1}{P_{total}}vs{y}_A$
• D. $\frac{1}{P_{total}}vs{y}_B+y_A$

Answer 1

Answer: (C)

$\frac{1}{P_{total}}vs{y}_A$

According to Raoult's law, vapor pressure of $A$ is $P_A=y_A{P}_{total}$

$y_A=P_A\times \frac{1}{P_{total}}$

$\therefore y_{A}vs\frac{1}{P_{total}}$ is a straight line.