Solutions Part 2

Concept:The mixture of acetone and $\mathrm{CS}_{2}$ shows positive deviation from Raoult's law.Explanation:For a solution showing positive deviation, the partial pressure of a component is greater than that predicted by Raoult's law.Raoult's law for $\mathrm{CS}_{2}$: $P_{\mathrm{CS}_{2}} = P_{\mathrm{CS}_{2}}^{\circ} \cdot X_{\mathrm{CS}_{2}}$ (a straight line).For positive deviation: $P_{\mathrm{CS}_{2}} > P_{\mathrm{CS}_{2}}^{\circ} \cdot X_{\mathrm{CS}_{2}}$.Therefore, the actual plot of $P_{\mathrm{CS}_{2}}$ vs $X_{\mathrm{CS}_{2}}$ lies above the straight line given by Raoult's law.Among the given graphs, the correct one shows a curve that is consistently above the ideal line.Answer:Option B.