Vapour pressure (in torr) of an ideal solution of two liquids $A$ and $B$ is given by : $P=52 X_{A}+114$ where $X_{\mathrm{A}}$ is the mole fraction of $A$ in the mixture. The vapour pressure (in torr) of equimolar mixture of the two liquids will be :

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Aicharya · Accepted Answer

Total V.P.,
$\mathrm{P}=\mathrm{P}_{\mathrm{A}}^{0} \mathrm{X}_{\mathrm{A}}+\mathrm{P}_{\mathrm{B}}^{0} \mathrm{X}_{\mathrm{B}}=\mathrm{P}_{\mathrm{A}}^{0} \mathrm{X}_{\mathrm{A}}+\mathrm{P}_{\mathrm{B}}^{\mathrm{O}}\left(1-\mathrm{X}_{\mathrm{A}}ight)$
$=\left(\mathrm{P}_{\mathrm{A}}^{\mathrm{o}}-\mathrm{P}_{\mathrm{B}}^{\mathrm{o}}ight) \mathrm{X}_{\mathrm{A}}+\mathrm{P}_{\mathrm{B}}^{\mathrm{o}}$
Thus, $\mathrm{P}_{\mathrm{B}}^{\circ}=114$ torr $; \mathrm{P}_{\mathrm{A}}^{\mathrm{o}}-\mathrm{P}_{\mathrm{B}}^{\mathrm{o}}=52$
or $\mathrm{P}_{\mathrm{A}}^{\mathrm{o}}=166$ torr
Hence $\mathrm{P}=166 \times \frac{1}{2}+114 \times \frac{1}{2}=140$ torr

Vapour pressure (in torr) of an ideal solution of two liquids $A$ and $B$ is given by : $P=52 X_{A}+114$…

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