JEE Main · 2026 · 23 Jan 2026 · Shift 1 · Solutions

A mixture of carbon disulphide and acetone shows positive deviation from Raoult's law because the weaker new interactions raise the escaping tendency of each component. The partial pressure of ${\text{CS}}_2$ therefore lies above the Raoult's law straight line $p_{{\text{CS}}_2}=p_{{\text{CS}}_2}^{\circ }{x}_{{\text{CS}}_2}$ across the whole composition range, touching that line only at $x_{{\text{CS}}_2}=1$ and approaching the steeper Henry's law tangent as $x_{{\text{CS}}_2}\to 0$. The correct plot is the one in which the ${\text{CS}}_2$ partial-pressure curve bows above the Raoult's law line and below the Henry's law line.