Question

The following is a graph plotted between the vapour pressure of two volatile liquids against their respective mole fractions.
Which of the following statements is/are correct ?

• A. When $x_A=1$ and $x_B=0$, then $p=p_A^{\circ }$
• B. When $x_B=1$ and $x_A=0$, then $p=p_B^{\circ }$
• C. When $x_A=1$ and $x_B=0$, then $p=p_B^{\circ }$
• D. When $x_B=1$ and $x_A=0$, then $p=p_A^{\circ }$

Answer 1

Answer: (A), (B)

When $x_A=1$ and $x_B=0$, then $p=p_A^{\circ }$
When $x_B=1$ and $x_A=0$, then $p=p_B^{\circ }$

In the graph, when $x_A=1and{x}_B=0$, then $p=p^{o}A$ since only vapour of A exist and when $x_B=1and{x}_A=0$ then $P=P_B^o$ since in that case only vapour of B exist.