Question

The total vapour pressure, ${\text{P}}_{\text{total}}$ (in torr) for a mixture of two volatile components, $A$ and $B$ is given by

${\text{P}}_{\text{total}}$ $=220-110$ ${\text{X}}_{\text{B}}$
Where, ${\text{X}}_{\text{B}}$ is mole fraction of component, $B$ in mixture.

Hence, pressure (in torr) of pure components, $A$ and $B$ are respectively:

• A. $220,110$
• B. $110,220$
• C. $220,330$
• D. $220,150$

Answer 1

The correct option is A $220,110$

$P_{total}=220-110X_B$

If $X_B=1$ i.e., $X_A$ is absent, pure B

$P_{total}:220-110\times \left(1\right)=220-110$

$P_B^0=110$ units

Now;

If $X_B=0$ i.e., $X_B$ is absent, pure A

$P_{Total}=220-110\times \left(0\right)$

$P_A^0=220$ units

$\therefore P_A^0=220$ torr; $P_B^0=110$ torr.